Paleolithic diet
Encyclopedia
Diet (nutrition)
In nutrition, diet is the sum of food consumed by a person or other organism. Dietary habits are the habitual decisions an individual or culture makes when choosing what foods to eat. With the word diet, it is often implied the use of specific intake of nutrition for health or weight-management...
known as the Paleolithic diet (abbreviated paleo diet or paleodiet), also popularly referred to as the caveman diet, Stone Age diet and hunter-gatherer diet, is a nutrition
Nutrition
Nutrition is the provision, to cells and organisms, of the materials necessary to support life. Many common health problems can be prevented or alleviated with a healthy diet....
al plan based on the presumed ancient diet of wild plants and animals that various hominid species habitually consumed during the Paleolithic
Paleolithic
The Paleolithic Age, Era or Period, is a prehistoric period of human history distinguished by the development of the most primitive stone tools discovered , and covers roughly 99% of human technological prehistory...
era—a period of about 2.5 million years duration that ended around 10,000 years ago with the development of agriculture. In common usage, such terms as the "Paleolithic diet" also refer to the actual ancestral human diet.
Centered on commonly available modern foods, the "contemporary" Paleolithic diet consists mainly of fish, grass-fed pasture raised meats, vegetables, fruit, root
Root
In vascular plants, the root is the organ of a plant that typically lies below the surface of the soil. This is not always the case, however, since a root can also be aerial or aerating . Furthermore, a stem normally occurring below ground is not exceptional either...
s, and nuts, and excludes grains, legumes, dairy products, salt, refined sugar, and processed oils.
First popularized in the mid-1970s by gastroenterologist Walter L. Voegtlin,
this nutritional concept has been promoted and adapted by a number of authors and researchers in several books and academic journals.
A common theme in evolutionary medicine
Evolutionary medicine
Evolutionary medicine or Darwinian medicine is the application of modern evolutionary theory to understanding health and disease. It provides a complementary scientific approach to the present mechanistic explanations that dominate medical science, and particularly modern medical education...
,
Paleolithic nutrition is based on the premise that modern humans are genetically adapted
Adaptation
An adaptation in biology is a trait with a current functional role in the life history of an organism that is maintained and evolved by means of natural selection. An adaptation refers to both the current state of being adapted and to the dynamic evolutionary process that leads to the adaptation....
to the diet of their Paleolithic ancestors and that human genetics
Genetics
Genetics , a discipline of biology, is the science of genes, heredity, and variation in living organisms....
have scarcely changed since the dawn of agriculture, and therefore that an ideal diet
Healthy diet
A healthy diet is one that helps maintain or improve general health. It is important for lowering many chronic health risks, such as obesity, heart disease, diabetes, hypertension and cancer. A healthy diet involves consuming appropriate amounts of all essential nutrients and an adequate amount of...
for human health and well-being is one that resembles this ancestral diet.
Proponents of this diet argue that modern human populations subsisting on traditional diets allegedly similar to those of Paleolithic hunter-gatherer
Hunter-gatherer
A hunter-gatherer or forage society is one in which most or all food is obtained from wild plants and animals, in contrast to agricultural societies which rely mainly on domesticated species. Hunting and gathering was the ancestral subsistence mode of Homo, and all modern humans were...
s are largely free of diseases of affluence
Diseases of affluence
Diseases of affluence is a term sometimes given to selected diseases and other health conditions which are commonly thought to be a result of increasing wealth in a society...
,
and that two small prospective studies of the Paleolithic diet in humans have shown some positive health outcomes.
Supporters point to several potentially therapeutic nutritional characteristics of allegedly preagricultural diets.
This dietary approach is a controversial topic amongst dietitian
Dietitian
Dietitians supervise the preparation and service of food, develop modified diets, participate in research, and educate individuals and groups on good nutritional habits. The goals of dietitians are to provide medical nutritional intervention, and to obtain, safely prepare, serve and advise on...
s
and anthropologists,
and an article on the National Health Service of England
National Health Service (England)
The National Health Service or NHS is the publicly funded healthcare system in England. It is both the largest and oldest single-payer healthcare system in the world. It is able to function in the way that it does because it is primarily funded through the general taxation system, similar to how...
Choices website suggests that it may be a fad diet.
Critics have argued that if hunter-gatherer societies failed to suffer from "diseases of civilization", this was due to a lack of calories in their diet, or a variety of other factors, rather than because of some special diet composition. Some researchers have taken issue with the accuracy of the diet's underlying evolutionary logic.
Also disputed are certain dietary recommendations and restrictions on the grounds that they provide no health benefits or pose health risks and are not likely to accurately reflect the features of ancient Paleolithic diets.
A 2011 ranking by US News & World Report, involving a panel of 22 experts, ranked the Paleo diet lowest of the 20 diets evaluated based on factors including health, weight-loss and ease of following. However, one expert involved in the ranking stated that a "true Paleo diet might be a great option: very lean, pure meats, lots of wild plants. The modern approximations … are far from it." Also, the ranking assumed a modernized offshoot to the paleo diet in which low-carb is emphasized, this diet specifically containing only 23% carbohydrates. Higher carbohydrate versions of the paleo diet, which allow for significant consumption of root vegetables,
were not a part of this ranking. Loren Cordain, a proponent of a low-carbohydrate Paleolithic diet, responded to the US News ranking, stating that their "conclusions are erroneous and misleading" and pointing out that "five studies, four since 2007, have experimentally tested contemporary versions of ancestral human diets and have found them to be superior to Mediterranean diets, diabetic diets and typical western diets in regards to weight loss, cardiovascular disease risk factors and risk factors for type 2 diabetes."
History
Gastroenterologist Walter L. Voegtlin was one of the first to suggest that following a diet similar to that of the Paleolithic era would improve a person's health.In 1975, he published a book
in which he argued that humans are carnivorous animals and that the ancestral Paleolithic diet was that of a carnivore — chiefly fats and protein, with only small amounts of carbohydrates.
His dietary prescriptions were based on his own medical treatments of various digestive problems, namely colitis
Colitis
In medicine, colitis refers to an inflammation of the colon and is often used to describe an inflammation of the large intestine .Colitides may be acute and self-limited or chronic, i.e...
, Crohn's disease
Crohn's disease
Crohn's disease, also known as regional enteritis, is a type of inflammatory bowel disease that may affect any part of the gastrointestinal tract from mouth to anus, causing a wide variety of symptoms...
, irritable bowel syndrome
Irritable bowel syndrome
Irritable bowel syndrome is a diagnosis of exclusion. It is a functional bowel disorder characterized by chronic abdominal pain, discomfort, bloating, and alteration of bowel habits in the absence of any detectable organic cause. In some cases, the symptoms are relieved by bowel movements...
and indigestion.
In 1985, S. Boyd Eaton and Melvin Konner
Melvin Konner
Melvin Konner, MD, PhD, is the Samuel Candler Dobbs Professor of Anthropology and Associate Professor of Psychiatry and Neurology at Emory University. He studied at Brooklyn College , CUNY , where he met Marjorie Shostak, whom he later married and with whom he had three children. He earned his PhD...
, both of Emory University
Emory University
Emory University is a private research university in metropolitan Atlanta, located in the Druid Hills section of unincorporated DeKalb County, Georgia, United States. The university was founded as Emory College in 1836 in Oxford, Georgia by a small group of Methodists and was named in honor of...
, published a key paper on Paleolithic nutrition in the New England Journal of Medicine
New England Journal of Medicine
The New England Journal of Medicine is an English-language peer-reviewed medical journal published by the Massachusetts Medical Society. It describes itself as the oldest continuously published medical journal in the world.-History:...
,
which caused the concept to gain mainstream medical attention.
Three years later, S. Boyd Eaton, Marjorie Shostak
Marjorie Shostak
Marjorie Shostak was an American anthropologist. Though she never received a formal degree in anthropology, she conducted extensive fieldwork among the !Kung San people of the Kalahari desert in south-western Africa and was widely known for her descriptions of the lives of women in this...
and Melvin Konner published a book about this nutritional approach,
which was based on achieving the same proportions of nutrients (fat, protein, and carbohydrates, as well as vitamins and minerals) as were present in the diets of late Paleolithic people, not on excluding foods that were not available before the development of agriculture. As such, this nutritional approach included skimmed milk, whole-grain bread, brown rice, and potatoes prepared without fat, on the premise that such foods supported a diet with the same macronutrient composition as the Paleolithic diet.
In 1989, these authors published a second book on Paleolithic nutrition.
Starting in 1989, Swedish medical doctor and scientist Staffan Lindeberg
Staffan Lindeberg
Staffan Lindeberg, M.D., Ph.D., is Associate Professor of Family Medicine at the Department of Medicine, University of Lund, Sweden...
, now associate professor at Lund University
Lund University
Lund University , located in the city of Lund in the province of Scania, Sweden, is one of northern Europe's most prestigious universities and one of Scandinavia's largest institutions for education and research, frequently ranked among the world's top 100 universities...
, Sweden
Sweden
Sweden , officially the Kingdom of Sweden , is a Nordic country on the Scandinavian Peninsula in Northern Europe. Sweden borders with Norway and Finland and is connected to Denmark by a bridge-tunnel across the Öresund....
, led scientific surveys of the non-westernized population on Kitava, one of the Trobriand Islands
Trobriand Islands
The Trobriand Islands are a 450 km² archipelago of coral atolls off the eastern coast of New Guinea. They are situated in Milne Bay Province in Papua New Guinea. Most of the population of 12,000 indigenous inhabitants live on the main island of Kiriwina, which is also the location of the...
of Papua New Guinea
Papua New Guinea
Papua New Guinea , officially the Independent State of Papua New Guinea, is a country in Oceania, occupying the eastern half of the island of New Guinea and numerous offshore islands...
. These surveys, collectively referred to as the Kitava Study, found that this population apparently did not suffer from stroke
Stroke
A stroke, previously known medically as a cerebrovascular accident , is the rapidly developing loss of brain function due to disturbance in the blood supply to the brain. This can be due to ischemia caused by blockage , or a hemorrhage...
, ischemic heart disease, diabetes, obesity
Obesity
Obesity is a medical condition in which excess body fat has accumulated to the extent that it may have an adverse effect on health, leading to reduced life expectancy and/or increased health problems...
or hypertension
Hypertension
Hypertension or high blood pressure is a cardiac chronic medical condition in which the systemic arterial blood pressure is elevated. What that means is that the heart is having to work harder than it should to pump the blood around the body. Blood pressure involves two measurements, systolic and...
. Starting with the first publication in 1993,
the Kitava Study has subsequently generated a number of scientific publications on the relationship between diet and western disease.
In 2003, Lindeberg published a Swedish language medical textbook on the subject.
In 2010, this book was wholly revised, updated and published for the first time in English. The 2010 book is geared towards both professionals and interested laypeople alike, cites more than 2000 references, and provides a comprehensive resource for the scientific foundation for the Paleolithic diet and the relationship between what humans eat and western diseases.
Since the end of the 1990s, a number of medical doctors and nutritionists
have advocated a return to a so-called Paleolithic (preagricultural) diet. Proponents of this nutritional approach have published books
and created websites
to promote their dietary prescriptions.
They have synthesized diets from modern foods that emulate nutritional characteristics of the ancient Paleolithic diet, some of which allow specific foods that would have been unavailable to pre-agricultural peoples, such as certain animal products (i.e. dairy), processed oils, and beverages.
Practices
Ecological niche
In ecology, a niche is a term describing the relational position of a species or population in its ecosystem to each other; e.g. a dolphin could potentially be in another ecological niche from one that travels in a different pod if the members of these pods utilize significantly different food...
s of Paleolithic humans. Based upon commonly available modern foods, it includes cultivated
Plant breeding
Plant breeding is the art and science of changing the genetics of plants in order to produce desired characteristics. Plant breeding can be accomplished through many different techniques ranging from simply selecting plants with desirable characteristics for propagation, to more complex molecular...
plants and domesticated animal meat as an alternative to the wild sources of the original preagricultural diet.
The ancestral human diet is inferred from historical and ethnographic
Ethnography
Ethnography is a qualitative method aimed to learn and understand cultural phenomena which reflect the knowledge and system of meanings guiding the life of a cultural group...
studies of modern-day hunter-gatherer
Hunter-gatherer
A hunter-gatherer or forage society is one in which most or all food is obtained from wild plants and animals, in contrast to agricultural societies which rely mainly on domesticated species. Hunting and gathering was the ancestral subsistence mode of Homo, and all modern humans were...
s as well as archaeological finds, anthropological
Biological anthropology
Biological anthropology is that branch of anthropology that studies the physical development of the human species. It plays an important part in paleoanthropology and in forensic anthropology...
evidence and application of optimal foraging theory
Optimal foraging theory
Optimal foraging theory is an idea in ecology based on the study of foraging behaviour and states that organisms forage in such a way as to maximize their net energy intake per unit time. In other words, they behave in such a way as to find, capture and consume food containing the most calories...
.
The Paleolithic diet consists of foods that can be hunted and fished, such as meat, offal
Offal
Offal , also called, especially in the United States, variety meats or organ meats, refers to the internal organs and entrails of a butchered animal. The word does not refer to a particular list of edible organs, which varies by culture and region, but includes most internal organs other than...
and seafood, and can be gathered, such as eggs, insects, fruit, nuts, seeds, vegetables, mushrooms, herbs and spices. Some sources advise eating only lean cuts of meat, free of food additive
Food additive
Food additives are substances added to food to preserve flavor or enhance its taste and appearance.Some additives have been used for centuries; for example, preserving food by pickling , salting, as with bacon, preserving sweets or using sulfur dioxide as in some wines...
s, preferably wild game
Game (food)
Game is any animal hunted for food or not normally domesticated. Game animals are also hunted for sport.The type and range of animals hunted for food varies in different parts of the world. This will be influenced by climate, animal diversity, local taste and locally accepted view about what can or...
meats and grass-fed beef since they contain higher levels of omega-3 fats compared with grain-produced domestic meats.
Food groups that advocates claim were rarely or never consumed by humans before the Neolithic (agricultural) revolution
Neolithic Revolution
The Neolithic Revolution was the first agricultural revolution. It was the transition from hunting and gathering to agriculture and settlement. Archaeological data indicates that various forms of plants and animal domestication evolved independently in 6 separate locations worldwide circa...
are excluded from the diet, mainly grains, legumes (e.g. beans and peanuts), dairy products, salt, refined sugar and processed oils, although some advocates consider the use of oil
Cooking oil
Cooking oil is purified fat of plant origin, which is usually liquid at room temperature ....
s with low omega-6/omega-3 ratios, such as olive oil
Olive oil
Olive oil is an oil obtained from the olive , a traditional tree crop of the Mediterranean Basin. It is commonly used in cooking, cosmetics, pharmaceuticals, and soaps and as a fuel for traditional oil lamps...
and canola oil, to be healthy and advisable.
Fructose
Fructose, or fruit sugar, is a simple monosaccharide found in many plants. It is one of the three dietary monosaccharides, along with glucose and galactose, that are absorbed directly into the bloodstream during digestion. Fructose was discovered by French chemist Augustin-Pierre Dubrunfaut in 1847...
, linoleic acid
Linoleic acid
Linoleic acid is an unsaturated n-6 fatty acid. It is a colorless liquid at room temperature. In physiological literature, it has a lipid number of 18:2...
, and gluten
Gluten
Gluten is a protein composite found in foods processed from wheat and related grain species, including barley and rye...
grains as the primary Neolithic agents responsible for modern diseases, and "the rest is just tinkering around the edges."
On the Paleolithic diet, practitioners are permitted to drink mainly water, and some advocates recommend tea as a healthy drink, but alcoholic and fermented beverages are restricted from the diet. Furthermore, eating a wide variety of plant foods is recommended to avoid high intakes of potentially harmful bioactive substances, such as goitrogen
Goitrogen
Goitrogens are substances that suppress the function of the thyroid gland by interfering with iodine uptake, which can, as a result, cause an enlargement of the thyroid, i.e., a goitre.-Goitrogenic drugs and chemicals:...
s, which are present in some roots, vegetables and seeds.
Unlike raw food diet
Raw foodism
Raw foodism is the practice of consuming uncooked, unprocessed, and often organic foods as a large percentage of the diet....
s, all foods may be cooked, without restrictions.
However, raw Paleolithic dieters exist who believe that humans have not adapted to cooked foods, and so they eat only foods which are both raw and Paleolithic.
According to certain proponents of the Paleolithic diet, practitioners should derive about 56–65% of their food energy
Food energy
Food energy is the amount of energy obtained from food that is available through cellular respiration.Food energy is expressed in food calories or kilojoules...
from animal foods
Animal source foods
Animal source foods include any food item that comes from an animal source such as meat, milk, fish, eggs, cheese and yogurt. Many individuals do not consume ASF or consume little ASF by either personal choice or necessity as ASF may not be accessible or available to these people.- Nutrition of...
and 36–45% from plant foods. They recommend a diet high in protein (19–35% energy) and relatively low in carbohydrates
Low-carbohydrate diet
Low-carbohydrate diets or low-carb diets are dietary programs that restrict carbohydrate consumption usually for weight control or for the treatment of obesity. Foods high in digestible carbohydrates are limited or replaced with foods containing a higher percentage of proteins and fats...
(22–40% energy), with a fat intake (28–58% energy) similar to or higher than that found in Western diet
Western pattern diet
The Western pattern diet, also called Western dietary pattern or the meat-sweet diet, is a dietary habit chosen by many people in developed countries, and increasingly in developing countries. It is characterized by high intakes of red meat, sugary desserts, high-fat foods, and refined grains...
s.
Furthermore, some proponents exclude from the diet foods which exhibit high glycemic indices
Glycemic index
The glycemic index, glycaemic index, or GI is a measure of the effects of carbohydrates on blood sugar levels. Carbohydrates that break down quickly during digestion and release glucose rapidly into the bloodstream have a high GI; carbohydrates that break down more slowly, releasing glucose more...
, such as potatoes. Staffan Lindeberg advocates a Paleolithic diet, but does not recommend any particular proportions of plants versus meat or macronutrient ratios.
According to Lindeberg, calcium
Calcium
Calcium is the chemical element with the symbol Ca and atomic number 20. It has an atomic mass of 40.078 amu. Calcium is a soft gray alkaline earth metal, and is the fifth-most-abundant element by mass in the Earth's crust...
supplementation
Dietary supplement
A dietary supplement, also known as food supplement or nutritional supplement, is a preparation intended to supplement the diet and provide nutrients, such as vitamins, minerals, fiber, fatty acids, or amino acids, that may be missing or may not be consumed in sufficient quantities in a person's diet...
may be considered when the intake of green leafy vegetables and other dietary sources of calcium is limited.
Rationale and evolutionary assumptions
According to S. Boyd Eaton, "we are the heirs of inherited characteristics accrued over millions of years; the vast majority of our biochemistry and physiology are tuned to life conditions that existed before the advent of agriculture some 10,000 years ago. Genetically our bodies are virtually the same as they were at the end of the Paleolithic era some 20,000 years ago."Paleolithic nutrition has its roots in evolutionary biology and is a common theme in evolutionary medicine
Evolutionary medicine
Evolutionary medicine or Darwinian medicine is the application of modern evolutionary theory to understanding health and disease. It provides a complementary scientific approach to the present mechanistic explanations that dominate medical science, and particularly modern medical education...
.
The reasoning underlying this nutritional approach is that natural selection
Natural selection
Natural selection is the nonrandom process by which biologic traits become either more or less common in a population as a function of differential reproduction of their bearers. It is a key mechanism of evolution....
had sufficient time to genetically adapt the metabolism
Metabolism
Metabolism is the set of chemical reactions that happen in the cells of living organisms to sustain life. These processes allow organisms to grow and reproduce, maintain their structures, and respond to their environments. Metabolism is usually divided into two categories...
and physiology
Physiology
Physiology is the science of the function of living systems. This includes how organisms, organ systems, organs, cells, and bio-molecules carry out the chemical or physical functions that exist in a living system. The highest honor awarded in physiology is the Nobel Prize in Physiology or...
of Paleolithic humans to the varying dietary conditions of that era. But in the 10,000 years since the invention of agriculture and its consequent major change in the human diet, natural selection has had too little time to make the optimal genetic adaptations to the new diet. Physiological and metabolic maladaptation
Maladaptation
A maladaptation is a trait that is more harmful than helpful. It is a term used when discussing both humans and animals in fields such as evolutionary biology, biology, psychology , sociology, and other fields where adaptation and responsive change may occur...
s result from the suboptimal genetic adaptations to the contemporary human diet, which in turn contribute to many of the so-called diseases of civilization
Lifestyle diseases
Lifestyle diseases are diseases that appear to increase in frequency as countries become more industrialized and people live longer...
.
More than 70% of the total daily energy consumed by all people in the United States comes from foods such as dairy products, cereals, refined sugars, refined vegetable oils and alcohol, that advocates of the Paleolithic diet assert contributed little or none of the energy in the typical preagricultural hominin diet. Proponents of this diet argue that excessive consumption of these novel Neolithic and Industrial era foods is responsible for the current epidemic levels of obesity
Obesity
Obesity is a medical condition in which excess body fat has accumulated to the extent that it may have an adverse effect on health, leading to reduced life expectancy and/or increased health problems...
, cardiovascular disease
Cardiovascular disease
Heart disease or cardiovascular disease are the class of diseases that involve the heart or blood vessels . While the term technically refers to any disease that affects the cardiovascular system , it is usually used to refer to those related to atherosclerosis...
, high blood pressure
Hypertension
Hypertension or high blood pressure is a cardiac chronic medical condition in which the systemic arterial blood pressure is elevated. What that means is that the heart is having to work harder than it should to pump the blood around the body. Blood pressure involves two measurements, systolic and...
, type 2 diabetes, osteoporosis
Osteoporosis
Osteoporosis is a disease of bones that leads to an increased risk of fracture. In osteoporosis the bone mineral density is reduced, bone microarchitecture is deteriorating, and the amount and variety of proteins in bone is altered...
and cancer
Cancer
Cancer , known medically as a malignant neoplasm, is a large group of different diseases, all involving unregulated cell growth. In cancer, cells divide and grow uncontrollably, forming malignant tumors, and invade nearby parts of the body. The cancer may also spread to more distant parts of the...
in the US and other contemporary Western populations.
Opposing views
The evolutionary assumptions underlying the Paleolithic diet have been disputed. According to Alexander Ströhle, Maike Wolters and Andreas Hahn, with the Department of Food Science at the University of Hanover, the statement that the human genomeHuman genome
The human genome is the genome of Homo sapiens, which is stored on 23 chromosome pairs plus the small mitochondrial DNA. 22 of the 23 chromosomes are autosomal chromosome pairs, while the remaining pair is sex-determining...
evolved during the Pleistocene
Pleistocene
The Pleistocene is the epoch from 2,588,000 to 11,700 years BP that spans the world's recent period of repeated glaciations. The name pleistocene is derived from the Greek and ....
(a period from 1,808,000 to 11,550 years ago) rests on an inadequate, but popular gene-centered view of evolution
Gene-centered view of evolution
The gene-centered view of evolution, gene selection theory or selfish gene theory holds that evolution occurs through the differential survival of competing genes, increasing the frequency of those alleles whose phenotypic effects successfully promote their own propagation, with gene defined as...
. They rely on Gray (2001)
to argue that evolution of organisms cannot be reduced to the genetic level with reference to mutation
Mutation
In molecular biology and genetics, mutations are changes in a genomic sequence: the DNA sequence of a cell's genome or the DNA or RNA sequence of a virus. They can be defined as sudden and spontaneous changes in the cell. Mutations are caused by radiation, viruses, transposons and mutagenic...
and that there is no one-to-one relationship between genotype
Genotype
The genotype is the genetic makeup of a cell, an organism, or an individual usually with reference to a specific character under consideration...
and phenotype
Phenotype
A phenotype is an organism's observable characteristics or traits: such as its morphology, development, biochemical or physiological properties, behavior, and products of behavior...
.
They further question the notion that 10,000 years is an insufficient period of time to ensure an adequate adaptation
Adaptation
An adaptation in biology is a trait with a current functional role in the life history of an organism that is maintained and evolved by means of natural selection. An adaptation refers to both the current state of being adapted and to the dynamic evolutionary process that leads to the adaptation....
to agrarian
Agrarian society
An agrarian society is a society that depends on agriculture as its primary means for support and sustenance. The society acknowledges other means of livelihood and work habits but stresses the importance of agriculture and farming, and was the most common form of socio-economic oganization for...
diets. For example, alleles conferring lactose tolerance increased to high frequencies in Europe just a few thousand years after animal husbandry
Animal husbandry
Animal husbandry is the agricultural practice of breeding and raising livestock.- History :Animal husbandry has been practiced for thousands of years, since the first domestication of animals....
was invented, and recent increases in the number of copies of the gene for salivary amylase, which digests starch, appear to be related to agriculture. Referring to Wilson (1994),
Ströhle et al. argue that "the number of generation
Generation
Generation , also known as procreation in biological sciences, is the act of producing offspring....
s that a species existed in the old environment
Natural environment
The natural environment encompasses all living and non-living things occurring naturally on Earth or some region thereof. It is an environment that encompasses the interaction of all living species....
was irrelevant, and that the response to the change of the environment of a species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
would depend on the heritability
Heredity
Heredity is the passing of traits to offspring . This is the process by which an offspring cell or organism acquires or becomes predisposed to the characteristics of its parent cell or organism. Through heredity, variations exhibited by individuals can accumulate and cause some species to evolve...
of the trait
Trait (biology)
A trait is a distinct variant of a phenotypic character of an organism that may be inherited, environmentally determined or be a combination of the two...
s, the intensity of selection
Selection
In the context of evolution, certain traits or alleles of genes segregating within a population may be subject to selection. Under selection, individuals with advantageous or "adaptive" traits tend to be more successful than their peers reproductively—meaning they contribute more offspring to the...
and the number of generations that selection acts."
They state that if the diet of Neolithic
Neolithic
The Neolithic Age, Era, or Period, or New Stone Age, was a period in the development of human technology, beginning about 9500 BC in some parts of the Middle East, and later in other parts of the world. It is traditionally considered as the last part of the Stone Age...
agriculturalists had been in discordance with their physiology
Physiology
Physiology is the science of the function of living systems. This includes how organisms, organ systems, organs, cells, and bio-molecules carry out the chemical or physical functions that exist in a living system. The highest honor awarded in physiology is the Nobel Prize in Physiology or...
, then this would have created a selection pressure for evolutionary change and modern humans, such as European
Genetic history of Europe
The genetic history of Europe can be inferred from the patterns of genetic diversity across continents and time. The primary data to develop historical scenarios coming from sequences of mitochondrial, Y-chromosome and autosomal DNA from modern populations and if available from ancient DNA...
s, whose ancestors have subsisted on agrarian diets for 400–500 generations should be somehow adequately adapted to it. In response to this argument, Wolfgang Kopp states that "we have to take into account that death from atherosclerosis and cardiovascular disease (CVD) occurs later during life, as a rule after the reproduction phase. Even a high mortality from CVD after the reproduction phase will create little selection pressure. Thus, it seems that a diet can be functional (it keeps us going) and dysfunctional (it causes health problems) at the same time." Moreover, S. Boyd Eaton and colleagues have indicated that "comparative genetic data provide compelling evidence against the contention that long exposure to agricultural and industrial circumstances has distanced us, genetically, from our Stone Age ancestors" however they mention exceptions such as increased lactose and gluten tolerance, which improve ability to digest dairy and grains, while other studies indicate that human adaptive evolution has accelerated since the Paleolithic.
Referencing Mahner et al. (2001)
and Ströhle et al. (2006),
Ströhle et al. state that "whatever is the fact, to think that a dietary factor is valuable (functional) to the organism only when there was ‘genetical adaptation’ and hence a new dietary factor is dysfunctional per se because there was no evolutionary adaptation to it, such a panselectionist
Molecular evolution
Molecular evolution is in part a process of evolution at the scale of DNA, RNA, and proteins. Molecular evolution emerged as a scientific field in the 1960s as researchers from molecular biology, evolutionary biology and population genetics sought to understand recent discoveries on the structure...
misreading of biological evolution seems to be inspired by a naive adaptationistic
Adaptationism
Adaptationism is a set of methods in the evolutionary sciences for distinguishing the products of adaptation from traits that arise through other processes. It is employed in fields such as ethology and evolutionary psychology that are concerned with identifying adaptations...
view of life."
Katharine Milton, a professor of physical anthropology
Physical anthropology
Biological anthropology is that branch of anthropology that studies the physical development of the human species. It plays an important part in paleoanthropology and in forensic anthropology...
at the University of California, Berkeley
University of California, Berkeley
The University of California, Berkeley , is a teaching and research university established in 1868 and located in Berkeley, California, USA...
, has also disputed the evolutionary logic upon which the Paleolithic diet is based. She questions the premise that the metabolism of modern humans must be genetically adapted to the dietary conditions of the Paleolithic. Relying on several of her previous publications,
Milton states that "there is little evidence to suggest that human nutritional requirements or human digestive physiology were significantly affected by such diets at any point in human evolution."
Evidence suggests the diet of Stone Age humans did include, in some form, the refined starches and grains that are excluded from the Paleolithic diet. There is evidence that Paleolithic societies were processing cereals for food use at least as early as 23,000
or 30,000 years ago,
and possibly as early as 105,000 or 200,000 years ago.
Plant-to-animal ratio
The specific plant to animal food ratio in the Paleolithic diet is also a matter of some dispute. The mean diet among modern hunter-gatherer societies is estimated to consist of 64–68% of animal calories and 32–36% of plant calories,with animal calories further divided between fished and hunted animals in varying proportions (most typically, with hunted animal food comprising 26–35% of the overall diet). As part of the so-called Man the Hunter
Man the Hunter
"Man the Hunter" was the name given to a 1966 symposium organized by Richard Lee and Irven DeVore. The symposium resulted in a book of the same title and attempted to bring together for the first time a comprehensive look at recent ethnographic research on hunter-gatherers.The symposium was held...
paradigm, this ratio was used as the basis of the earliest forms of the Paleolithic diet by Voegtlin, Eaton and others. To this day, many advocates of the Paleolithic diet consider high percentage of animal flesh to be one of the key features of the diet.
However, great disparities do exist, even between different modern hunter-gatherer societies. The animal-derived calorie percentage ranges from 25% in the Gwi
Gana and Gwi bushmen
The Gana and Gwi bushmen are peoples indigenous to the central Kalahari region of Botswana.Since the mid-1990s the government of Botswana has been in the process of relocating the bushmen, against their will, to relocation camps around the periphery of the Kalahari Central Game Reserve...
people of southern Africa, to 99% in Alaskan Nunamiut
Nunamiut
The Nunamiut people are a semi-nomadic inland Inupiaq Eskimos located in northern and northwestern Alaska, mostly around the Anaktuvuk Pass, Alaska, whose ancestors date back hundreds of years.-History:...
. The animal-derived percentage value is skewed upwards by polar hunter-gatherer societies, who have no choice but to eat animal food because of the inaccessibility of plant foods. Since those environments were only populated relatively recently (for example, Paleo-Indian ancestors of Nunamiut are thought to have arrived to Alaska no earlier than 30,000 years ago), such diets represent recent adaptations rather than conditions that shaped human evolution during much of the Paleolithic. More generally, hunting and fishing tend to provide a higher percentage of energy in forager societies living at higher latitudes. Excluding cold-climate and equestrian foragers results in a diet structure of 52% plant calories, 26% hunting calories, and 22% fishing calories. Furthermore, those numbers may still not be representative of a typical Stone Age diet, since fishing did not become common in many parts of the world until the Upper Paleolithic period 35-40 thousand years ago, and early humans' hunting abilities were relatively limited , compared to modern hunter-gatherers, as well (the oldest incontrovertible evidence for the existence of bows only dates to about 8000 BCE,
and nets and traps were invented 22,000 to 29,000 years ago.)
An extreme version of this line of thought posits that, up until the Upper Paleolithic, humans were frugivore
Frugivore
A frugivore is a fruit eater. It can be any type of herbivore or omnivore where fruit is a preferred food type. Because approximately 20% of all mammalian herbivores also eat fruit, frugivory is considered to be common among mammals. Since frugivores eat a lot of fruit they are highly dependent...
s (fruit eaters), who supplemented their meals with carrion, eggs, and small prey such as baby birds and mussel
Mussel
The common name mussel is used for members of several families of clams or bivalvia mollusca, from saltwater and freshwater habitats. These groups have in common a shell whose outline is elongated and asymmetrical compared with other edible clams, which are often more or less rounded or oval.The...
s, and, only on rare occasions, managed to kill and consume big game such as antelope
Antelope
Antelope is a term referring to many even-toed ungulate species indigenous to various regions in Africa and Eurasia. Antelopes comprise a miscellaneous group within the family Bovidae, encompassing those old-world species that are neither cattle, sheep, buffalo, bison, nor goats...
s.
This view is supported by the studies of higher apes, particularly chimpanzee
Chimpanzee
Chimpanzee, sometimes colloquially chimp, is the common name for the two extant species of ape in the genus Pan. The Congo River forms the boundary between the native habitat of the two species:...
s. Chimpanzees are closest to humans genetically, sharing more than 98% of their DNA code with humans, and their digestive tract is functionally very similar to that of humans. Chimpanzees are primarily frugivore
Frugivore
A frugivore is a fruit eater. It can be any type of herbivore or omnivore where fruit is a preferred food type. Because approximately 20% of all mammalian herbivores also eat fruit, frugivory is considered to be common among mammals. Since frugivores eat a lot of fruit they are highly dependent...
s, but they could and would consume and digest animal flesh, given the opportunity. However, their actual diet in the wild is about 95% plant-based, with the remaining 5% filled with insects, eggs, and baby animals.
Some comparative studies of human and higher primate digestive tracts do suggest that humans have evolved to obtain greater amounts of calories from high-quality sources such as animal foods, allowing them to shrink the size of the gastrointestinal tract, relative to body mass, and to increase the brain mass instead.
Nevertheless, modern humans' digestive organs and mechanisms, such as dentition, stomach pH, and gut size, remain much closer to chimpanzees than to obligate carnivores or true omnivores such as bears and raccoons.
A difficulty with this point of view is that humans are established to require certain long-chain polyunsaturated fats (LCP), such as AA
Arachidonic acid
Arachidonic acid is a polyunsaturated omega-6 fatty acid 20:4.It is the counterpart to the saturated arachidic acid found in peanut oil, Arachidonic acid (AA, sometimes ARA) is a polyunsaturated omega-6 fatty acid 20:4(ω-6).It is the counterpart to the saturated arachidic acid found in peanut oil,...
and DHA
Docosahexaenoic acid
Docosahexaenoic acid is an omega-3 fatty acid that is a primary structural component of the human brain and retina. In chemical structure, DHA is a carboxylic acid with a 22-carbon chain and six cis double bonds; the first double bond is located at the third carbon from the omega end...
.
Human LCP requirements are much greater than chimpanzees' because of humans' larger brain mass, and humans' abilities to synthesize them from other nutrients are poor, suggesting readily available external sources.
But LCPs are nonexistent in plants, and DHA is also almost nonexistent in most tissues of warm-climate animals. Pregnant and lactating females require 100 mg of DHA per day.
The primary source of DHA in the modern human diet is fish. Despite the general shortage of evidence for extensive fishing, thought to require relatively sophisticated tools which have become available only in the last 30–50 thousand years, it has been argued that exploitation of coastal fauna somehow provided hominids with abundant LCP. Alternatively, it has been proposed that early hominids frequently scavenged predators' kills and consumed parts which were left untouched by predators, most commonly the brain, which is very high in AA and DHA. Just 100 g of scavenged African ruminant brain matter provide more DHA than is consumed by a typical modern U.S. adult in the course of a week.
Other authors suggested that human ability to convert alpha-Linolenic acid
Alpha-linolenic acid
α-Linolenic acid is an organic compound found in many common vegetable oils. In terms of its structure, it is named all-cis-9,12,15-octadecatrienoic acid. In physiological literature, it is given the name 18:3 ....
into DHA, while poor, is, nevertheless, adequate to prevent DHA deficiency in a plant-based diet.
Nutritional factors and health effects
Neolithic Revolution
The Neolithic Revolution was the first agricultural revolution. It was the transition from hunting and gathering to agriculture and settlement. Archaeological data indicates that various forms of plants and animal domestication evolved independently in 6 separate locations worldwide circa...
, humans started consuming large amounts of dairy products, beans, cereals, alcohol and salt. In the late 18th and early 19th centuries, the Industrial revolution
Industrial Revolution
The Industrial Revolution was a period from the 18th to the 19th century where major changes in agriculture, manufacturing, mining, transportation, and technology had a profound effect on the social, economic and cultural conditions of the times...
led to the large scale development of mechanized food processing
Food processing
Food processing is the set of methods and techniques used to transform raw ingredients into food or to transform food into other forms for consumption by humans or animals either in the home or by the food processing industry...
techniques and intensive livestock farming
Factory farming
Factory farming is a term referring to the process of raising livestock in confinement at high stocking density, where a farm operates as a factory — a practice typical in industrial farming by agribusinesses. The main products of this industry are meat, milk and eggs for human consumption...
methods, that enabled the production of refined cereal
Refined grains
Refined grains, in contrast to whole grains, refers to grain products consisting of grains or grain flours that have been significantly modified from their natural composition. The modification process generally involves the mechanical removal of bran and germ, either through grinding or selective...
s, refined sugars and refined vegetable oils, as well as fattier domestic meats, which have become major components of Western diets.
Such food staples have fundamentally altered several key nutritional characteristics of the human diet since the Paleolithic era, including glycemic load
Glycemic load
The glycemic load is a ranking system for carbohydrate content in food portions based on their glycemic index and a standardized portion size of 100g. Glycemic load or GL combines both the quality and quantity of carbohydrate in one number. It is the best way to predict blood glucose values of...
, fatty acid
Fatty acid
In chemistry, especially biochemistry, a fatty acid is a carboxylic acid with a long unbranched aliphatic tail , which is either saturated or unsaturated. Most naturally occurring fatty acids have a chain of an even number of carbon atoms, from 4 to 28. Fatty acids are usually derived from...
composition, macronutrient composition, micronutrient density
Nutrient density
The term nutrient density has several meanings.Most commonly, nutrient density is defined as a ratio of nutrient content to the total energy content . Nutrient-dense food is opposite to energy-dense food...
, acid-base balance
Acid-base homeostasis
Acid–base homeostasis is the part of human homeostasis concerning the proper balance between acids and bases, in other words, the pH. The body is very sensitive to its pH level, so strong mechanisms exist to maintain it...
, sodium
Sodium
Sodium is a chemical element with the symbol Na and atomic number 11. It is a soft, silvery-white, highly reactive metal and is a member of the alkali metals; its only stable isotope is 23Na. It is an abundant element that exists in numerous minerals, most commonly as sodium chloride...
-potassium
Potassium
Potassium is the chemical element with the symbol K and atomic number 19. Elemental potassium is a soft silvery-white alkali metal that oxidizes rapidly in air and is very reactive with water, generating sufficient heat to ignite the hydrogen emitted in the reaction.Potassium and sodium are...
ratio, and fiber
Fiber
Fiber is a class of materials that are continuous filaments or are in discrete elongated pieces, similar to lengths of thread.They are very important in the biology of both plants and animals, for holding tissues together....
content.
These dietary compositional changes have been theorized as risk factor
Risk factor
In epidemiology, a risk factor is a variable associated with an increased risk of disease or infection. Sometimes, determinant is also used, being a variable associated with either increased or decreased risk.-Correlation vs causation:...
s in the pathogenesis
Pathogenesis
The pathogenesis of a disease is the mechanism by which the disease is caused. The term can also be used to describe the origin and development of the disease and whether it is acute, chronic or recurrent...
of many of the so-called "diseases of civilization" and other chronic illnesses that are widely prevalent in Western societies,
including obesity
Obesity
Obesity is a medical condition in which excess body fat has accumulated to the extent that it may have an adverse effect on health, leading to reduced life expectancy and/or increased health problems...
,
cardiovascular disease
Cardiovascular disease
Heart disease or cardiovascular disease are the class of diseases that involve the heart or blood vessels . While the term technically refers to any disease that affects the cardiovascular system , it is usually used to refer to those related to atherosclerosis...
,
high blood pressure
Hypertension
Hypertension or high blood pressure is a cardiac chronic medical condition in which the systemic arterial blood pressure is elevated. What that means is that the heart is having to work harder than it should to pump the blood around the body. Blood pressure involves two measurements, systolic and...
,
type 2 diabetes,
osteoporosis
Osteoporosis
Osteoporosis is a disease of bones that leads to an increased risk of fracture. In osteoporosis the bone mineral density is reduced, bone microarchitecture is deteriorating, and the amount and variety of proteins in bone is altered...
,
autoimmune disease
Autoimmune disease
Autoimmune diseases arise from an overactive immune response of the body against substances and tissues normally present in the body. In other words, the body actually attacks its own cells. The immune system mistakes some part of the body as a pathogen and attacks it. This may be restricted to...
s,
colorectal cancer
Colorectal cancer
Colorectal cancer, commonly known as bowel cancer, is a cancer caused by uncontrolled cell growth , in the colon, rectum, or vermiform appendix. Colorectal cancer is clinically distinct from anal cancer, which affects the anus....
,
myopia
Myopia
Myopia , "shortsightedness" ) is a refractive defect of the eye in which collimated light produces image focus in front of the retina under conditions of accommodation. In simpler terms, myopia is a condition of the eye where the light that comes in does not directly focus on the retina but in...
,
acne
Acne
Acne is a general term used for acneiform eruptions. It is usually used as a synonym for acne vulgaris, but may also refer to:*Acne aestivalis*Acne conglobata*Acne cosmetica*Acne fulminans*Acne keloidalis nuchae*Acne mechanica...
,
depression,
and diseases related to vitamin and mineral deficiencies
Mineral deficiency
Mineral deficiency refers to a hypoalimentation of dietary minerals.Examples include:* Zinc deficiency* Iron deficiency* Magnesium deficiency...
.
Protein and carbohydrates
"The increased contribution of carbohydrate from grains to the human diet following the agricultural revolution has effectively diluted the protein content of the human diet."In modern hunter-gatherer diets, dietary protein is characteristically elevated (19–35% of energy) at the expense of carbohydrate (22–40% of energy).
High-protein diets may have a cardiovascular protective effect and may represent an effective weight loss strategy for the overweight or obese. Furthermore, carbohydrate restriction may help prevent obesity and type 2 diabetes,
as well as atherosclerosis
Atherosclerosis
Atherosclerosis is a condition in which an artery wall thickens as a result of the accumulation of fatty materials such as cholesterol...
. Carbohydrate deprivation to the point of ketosis
Ketosis
Ketosis is a state of elevated levels of ketone bodies in the body. It is almost always generalized throughout the body, with hyperketonemia, that is, an elevated level of ketone bodies in the blood. Ketone bodies are formed by ketogenesis when the liver glycogen stores are depleted...
has been argued both to have negative
and positive effects on health.
Critics argue that there is insufficient data to identify the relative proportions of plant and animal foods consumed on average by Paleolithic humans in general, and they stress the rich variety of ancient and modern hunter-gatherer diets. Furthermore, preagricultural hunter-gatherers may have generally consumed large quantities of carbohydrates in the form of carbohydrate-rich tuber
Tuber
Tubers are various types of modified plant structures that are enlarged to store nutrients. They are used by plants to survive the winter or dry months and provide energy and nutrients for regrowth during the next growing season and they are a means of asexual reproduction...
s (plant underground storage organ
Storage organ
A storage organ is a part of a plant specifically modified for storage of energy or water. Storage organs often grow underground, where they are better protected from attack by herbivores. Plants that have an underground storage organ are called geophytes in the Raunkiær plant life-form...
s). According to Staffan Lindeberg, an advocate of the Paleolithic diet, a plant-based diet rich in carbohydrates is consistent with the human evolutionary past
Human evolution
Human evolution refers to the evolutionary history of the genus Homo, including the emergence of Homo sapiens as a distinct species and as a unique category of hominids and mammals...
.
It has also been argued that relative freedom from degenerative diseases was, and still is, characteristic of all hunter-gatherer societies irrespective of the macronutrient characteristics of their diets.
Marion Nestle
Marion Nestle
Marion Nestle, Ph.D., M.P.H., is the Paulette Goddard Professor of Nutrition, Food Studies, and Public Health at New York University, in the department that she chaired from 1988 through 2003. Her degrees include a Ph.D. in molecular biology and an M.P.H. in public health nutrition, both from the...
, a professor in the Department of Nutrition and Food Studies at New York University
New York University
New York University is a private, nonsectarian research university based in New York City. NYU's main campus is situated in the Greenwich Village section of Manhattan...
, judging from research relating nutritional factors to chronic disease risks and to observations of exceptionally low chronic disease rates among people eating vegetarian, Mediterranean
Mediterranean diet
The Mediterranean diet is a modern nutritional recommendation inspired by the traditional dietary patterns of southern Italy, Crete and much of the rest of Greece in the 1960s....
and Asian
Asian cuisine
Asian cuisine styles can be broken down into several tiny regional styles that have roots in the peoples and cultures of those regions. The major types can be roughly defined as East Asian with its origins in Imperial China and now encompassing modern Japan and the Korean peninsula; Southeast Asian...
diets, has suggested that plant-based diets may be most associated with health
Health
Health is the level of functional or metabolic efficiency of a living being. In humans, it is the general condition of a person's mind, body and spirit, usually meaning to be free from illness, injury or pain...
and longevity
Longevity
The word "longevity" is sometimes used as a synonym for "life expectancy" in demography or known as "long life", especially when it concerns someone or something lasting longer than expected ....
.
Fatty acids
Hunter-gatherer diets have been argued to maintain relatively high levels of monounsaturatedMonounsaturated fat
In biochemistry and nutrition, monounsaturated fats or MUFA are fatty acids that have one double bond in the fatty acid chain and all of the remainder of the carbon atoms in the chain are single-bonded...
and polyunsaturated
Polyunsaturated fatty acid
Polyunsaturated fatty acids are fatty acids that contain more than one double bond in their backbone. This class includes many important compounds, such as essential fatty acids and those that give drying oils their characteristic property....
fats, moderate levels of saturated fat
Saturated fat
Saturated fat is fat that consists of triglycerides containing only saturated fatty acids. Saturated fatty acids have no double bonds between the individual carbon atoms of the fatty acid chain. That is, the chain of carbon atoms is fully "saturated" with hydrogen atoms...
s (10–15% of total food energy
Food energy
Food energy is the amount of energy obtained from food that is available through cellular respiration.Food energy is expressed in food calories or kilojoules...
)
as well as a low omega-6
Omega-6 fatty acid
n−6 fatty acids are a family of unsaturated fatty acids that have in common a final carbon–carbon double bond in the n−6 position, that is, the sixth bond, counting from the methyl end.The biological effects of the n−6 fatty acids are largely mediated by their conversion to n-6 eicosanoids...
:omega-3
Omega-3 fatty acid
N−3 fatty acids are essential unsaturated fatty acids with a double bond starting after the third carbon atom from the end of the carbon chain....
fatty acid
Fatty acid
In chemistry, especially biochemistry, a fatty acid is a carboxylic acid with a long unbranched aliphatic tail , which is either saturated or unsaturated. Most naturally occurring fatty acids have a chain of an even number of carbon atoms, from 4 to 28. Fatty acids are usually derived from...
ratio.
Cows fed a grass-based diet produce significant amounts of omega-3 fatty acid
Omega-3 fatty acid
N−3 fatty acids are essential unsaturated fatty acids with a double bond starting after the third carbon atom from the end of the carbon chain....
s compared to grain-fed animals, while minimizing trans fat
Trans fat
Trans fat is the common name for unsaturated fat with trans-isomer fatty acid. Because the term refers to the configuration of a double carbon-carbon bond, trans fats are sometimes monounsaturated or polyunsaturated, but never saturated....
s and saturated fats. The diet does include a significant amount of cholesterol due to the inclusion of lean meat.
These nutritional factors may serve to inhibit the development of cardiovascular disease. This high ratio of polyunsaturated to saturated fats has been challenged. While a low saturated fat intake was argued for it has been argued that hunter-gatherers would selectively hunt fatter animals and utilise the fattiest parts of the animals (such as bone marrow).
Energy density
The Paleolithic diet has lower energy density than the typical diet consumed by modern humans.This is especially true in primarily plant-based/vegetarian versions of the diet, but it still holds if substantial amounts of lean meat are included in calculations. For example, most fruits and berries contain 0.4 to 0.8 calories per gram, vegetables can be even lower than that (cucumber
Cucumber
The cucumber is a widely cultivated plant in the gourd family Cucurbitaceae, which includes squash, and in the same genus as the muskmelon. The plant is a creeping vine which bears cylindrical edible fruit when ripe. There are three main varieties of cucumber: "slicing", "pickling", and...
s contain only 0.16 calories per gram).
Lean game meat, such as cooked wild rabbit, is more energy-dense (up to 1.7 calories per gram), but it does not constitute the bulk of the diet by mass/volume at the recommended plant/animal ratios, and it does not reach the densities of many processed foods commonly consumed by modern humans: most McDonalds sandwiches such as the Big Mac
Big Mac
The Big Mac is a hamburger sold by McDonald's, an international fast food restaurant chain. It is one of the company's signature products...
average 2.4 to 2.8 calories/gram,
and sweets such as cookies and chocolate bars commonly exceed 4 calories/gram.
There is substantial evidence that people consuming high energy-density diets are prone to overeating and they are at a greater risk of weight gain. Conversely, low caloric density diets tend to provide a greater satiety feeling at the same energy intake, and they have been shown effective at achieving weight loss in overweight individuals without explicit caloric restrictions.
Even some authors who may otherwise appear to be critical of the concept of Paleolithic diet have argued that high energy density of modern diets, as compared to ancestral/primate diets, contributes to the rate of diseases of affluence in the industrial world.
Micronutrient density
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Omega-3 fatty acid
N−3 fatty acids are essential unsaturated fatty acids with a double bond starting after the third carbon atom from the end of the carbon chain....
s and other micronutrient
Micronutrient
Micronutrients are nutrients required by humans and other living things throughout life in small quantities to orchestrate a whole range of physiological functions, but which the organism itself cannot produce. For people, they include dietary trace minerals in amounts generally less than 100...
s, such as iodine
Iodine
Iodine is a chemical element with the symbol I and atomic number 53. The name is pronounced , , or . The name is from the , meaning violet or purple, due to the color of elemental iodine vapor....
, iron
Iron
Iron is a chemical element with the symbol Fe and atomic number 26. It is a metal in the first transition series. It is the most common element forming the planet Earth as a whole, forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust...
, zinc
Zinc
Zinc , or spelter , is a metallic chemical element; it has the symbol Zn and atomic number 30. It is the first element in group 12 of the periodic table. Zinc is, in some respects, chemically similar to magnesium, because its ion is of similar size and its only common oxidation state is +2...
, copper
Copper
Copper is a chemical element with the symbol Cu and atomic number 29. It is a ductile metal with very high thermal and electrical conductivity. Pure copper is soft and malleable; an exposed surface has a reddish-orange tarnish...
, and selenium
Selenium
Selenium is a chemical element with atomic number 34, chemical symbol Se, and an atomic mass of 78.96. It is a nonmetal, whose properties are intermediate between those of adjacent chalcogen elements sulfur and tellurium...
, that are crucial for proper brain function and development. Terrestrial animal foods, such as muscle, brain, bone marrow
Bone marrow
Bone marrow is the flexible tissue found in the interior of bones. In humans, bone marrow in large bones produces new blood cells. On average, bone marrow constitutes 4% of the total body mass of humans; in adults weighing 65 kg , bone marrow accounts for approximately 2.6 kg...
, thyroid gland, and other organs
Offal
Offal , also called, especially in the United States, variety meats or organ meats, refers to the internal organs and entrails of a butchered animal. The word does not refer to a particular list of edible organs, which varies by culture and region, but includes most internal organs other than...
, also represent a primary source of these nutrients. Calcium-poor grains and legumes are excluded from the diet.
Two notable exceptions are calcium
Calcium
Calcium is the chemical element with the symbol Ca and atomic number 20. It has an atomic mass of 40.078 amu. Calcium is a soft gray alkaline earth metal, and is the fifth-most-abundant element by mass in the Earth's crust...
(see below) and vitamin D
Vitamin D
Vitamin D is a group of fat-soluble secosteroids. In humans, vitamin D is unique both because it functions as a prohormone and because the body can synthesize it when sun exposure is adequate ....
, both of which may be present in the diet in inadequate quantities. Modern humans require much more vitamin D than hunter-gatherers, because they do not get the same amount of exposure to sun. This need is commonly satisfied in developed countries by artificially fortifying dairy products with the vitamin. In order to avoid deficiency, a modern human on a hunter-gatherer diet would have to take artificial supplements of the vitamin, ensure adequate intake of certain fatty fish,
or increase the amount of exposure to sunlight (it's been estimated that 30 minutes of exposure to mid-day sun twice a week is adequate for most people.)
Fibre content and glycemic load
Despite its relatively low carbohydrate content, the Paleolithic diet involves a substantial increase in consumption of fruit and vegetables, compared to the Western diet, potentially as high as 1.65 to 1.9 kg/day.This leads to fiber intake which is significantly larger than either current or recommended values. Hunter-gatherer diets, which rely on uncultivated, heavily fibrous fruit and vegetables, contain even more. Fiber intake in preagricultural diets is thought to have exceeded 100 g/day. This is dramatically higher than the actual current U.S. intake of 15 g/day.
Glycemic index
The glycemic index, glycaemic index, or GI is a measure of the effects of carbohydrates on blood sugar levels. Carbohydrates that break down quickly during digestion and release glucose rapidly into the bloodstream have a high GI; carbohydrates that break down more slowly, releasing glucose more...
.
Moreover, dairy products, such as milk, have low glycemic indices, but are highly insulinotropic, with an insulin index
Insulin index
The Insulin Index is a measure used to quantify the typical insulin response to various foods. The index is similar to the Glycemic Index and Glycemic Load, but rather than relying on blood glucose levels, the Insulin Index is based upon blood insulin levels...
similar to that of white bread.
However, in fermented milk products, such as yogurt, the presence of organic acids may counteract the insulinotropic effect of milk in mixed meals.
These dietary characteristics may lower risk of diabetes, obesity and other related syndrome X
Metabolic syndrome
Metabolic syndrome is a combination of medical disorders that, when occurring together, increase the risk of developing cardiovascular disease and diabetes. It affects one in five people in the United States and prevalence increases with age...
diseases by placing less stress on the pancreas
Pancreas
The pancreas is a gland organ in the digestive and endocrine system of vertebrates. It is both an endocrine gland producing several important hormones, including insulin, glucagon, and somatostatin, as well as a digestive organ, secreting pancreatic juice containing digestive enzymes that assist...
to produce insulin
Insulin
Insulin is a hormone central to regulating carbohydrate and fat metabolism in the body. Insulin causes cells in the liver, muscle, and fat tissue to take up glucose from the blood, storing it as glycogen in the liver and muscle....
, and preventing insulin insensitivity.
Sodium-potassium ratio
It has been estimated that people in the Paleolithic era consumed 11,000 mg of potassium and 700 mg of sodium daily.The modern Paleolithic diet includes neither processed foods
Food processing
Food processing is the set of methods and techniques used to transform raw ingredients into food or to transform food into other forms for consumption by humans or animals either in the home or by the food processing industry...
(which often contains salt as a preservative) nor added salt as a condiment. The sodium intake of the diet (~726mg) is lower than average U.S. values (3,271mg) or recommended values (1,500mg). Further, since potassium-rich fruits and vegetables compose ~30% of the daily energy, the potassium content (~9,062mg) is nearly 3.5 times greater than average values (2,620mg) in the U.S. diet.
The dominance of sodium over potassium to sodium in the U.S. diet adversely affects cardiovascular function and contributes to hypertension
Hypertension
Hypertension or high blood pressure is a cardiac chronic medical condition in which the systemic arterial blood pressure is elevated. What that means is that the heart is having to work harder than it should to pump the blood around the body. Blood pressure involves two measurements, systolic and...
and stroke
Stroke
A stroke, previously known medically as a cerebrovascular accident , is the rapidly developing loss of brain function due to disturbance in the blood supply to the brain. This can be due to ischemia caused by blockage , or a hemorrhage...
.,
so the Paleolithic diet inverts this ratio.
Calcium and acid-base balance
Diets containing high amounts of salt or cereals and other foods that induce and sustain increased acidity of body fluid may contribute to the development of osteoporosis and renal stones, loss of muscle mass, and age-related renal insufficiency due to the body's use of calcium to buffer pH. The paleo diet may not contain the high levels of calcium recommended in the U.S. to prevent these effects. However, because of the absence of acid yielding cereals and energy-dense, nutrient-poor foods in the hunter-gatherer diet - foods that displace base-yielding fruits and vegetables - the diet produces a net base load on the body, as opposed to a net acid load, which may reduce calcium excretion.Bioactive substances and antinutrients
Furthermore, cereal grains, legumes and milk contain bioactiveBiological activity
In pharmacology, biological activity or pharmacological activity describes the beneficial or adverse effects of a drug on living matter. When a drug is a complex chemical mixture, this activity is exerted by the substance's active ingredient or pharmacophore but can be modified by the other...
substances, such as gluten and casein, which have been implicated in the development of various health problems. Consumption of gluten
Gluten
Gluten is a protein composite found in foods processed from wheat and related grain species, including barley and rye...
, a component of certain grains, such as wheat
Wheat
Wheat is a cereal grain, originally from the Levant region of the Near East, but now cultivated worldwide. In 2007 world production of wheat was 607 million tons, making it the third most-produced cereal after maize and rice...
, rye
Rye
Rye is a grass grown extensively as a grain and as a forage crop. It is a member of the wheat tribe and is closely related to barley and wheat. Rye grain is used for flour, rye bread, rye beer, some whiskeys, some vodkas, and animal fodder...
and barley
Barley
Barley is a major cereal grain, a member of the grass family. It serves as a major animal fodder, as a base malt for beer and certain distilled beverages, and as a component of various health foods...
, is known to have adverse health effects in individuals suffering from a range of gluten sensitivities
Gluten sensitivity
Gluten sensitivity belongs to a spectrum of disorders in which gluten has an adverse effect on the body. It can be defined as a non-allergic and non-autoimmune condition in which the consumption of gluten can lead to symptoms similar to those observed in coeliac disease or wheat allergy .Gluten...
, including celiac disease. Since the Paleolithic diet is devoid of cereal grains, it is free of gluten
Gluten-free diet
A gluten-free diet is a diet that excludes foods containing gluten. Gluten is a protein found in wheat , barley, rye, malts and triticale. It is used as a food additive in the form of a flavoring, stabilizing or thickening agent, often as "dextrin"...
. The paleodiet is also casein-free
Gluten-free, casein-free diet
A gluten-free casein-free diet eliminates dietary intake of the naturally occurring proteins gluten and casein .-Controversial autism diet:...
. Casein
Casein
Casein is the name for a family of related phosphoprotein proteins . These proteins are commonly found in mammalian milk, making up 80% of the proteins in cow milk and between 60% and 65% of the proteins in human milk....
is a protein found in milk and dairy products, which may impair glucose tolerance in humans.
Compared to Paleolithic food groups, cereal grains and legumes contain high amounts of antinutrients, including alkylresorcinols
Alkylresorcinols
Alkylresorcinols are phenolic lipids present in high amounts in the bran layer of wheat and rye...
, alpha-amylase
Alpha-Amylase
α-Amylase is an enzyme that hydrolyses alpha-bonds of large alpha-linked polysaccharides such as starch and glycogen, yielding glucose and maltose. It is the major form of amylase found in humans and other mammals...
inhibitors, protease inhibitor
Protease inhibitor (biology)
In biology and biochemistry, protease inhibitors are molecules that inhibit the function of proteases. Many naturally occurring protease inhibitors are proteins....
s, lectin
Lectin
Lectins are sugar-binding proteins that are highly specific for their sugar moieties. They play a role in biological recognition phenomena involving cells and proteins. For example, some viruses use lectins to attach themselves to the cells of the host organism during infection...
s and phytates, substances known to interfere with the body's absorption of many key nutrients. Molecular-mimicking
Molecular mimicry
Molecular mimicry is defined as the theoretical possibility that sequence similarities between foreign and self-peptides are sufficient to result in the cross-activation of autoreactive T or B cells by pathogen-derived peptides...
proteins, which are basically made up of strings of amino acid
Amino acid
Amino acids are molecules containing an amine group, a carboxylic acid group and a side-chain that varies between different amino acids. The key elements of an amino acid are carbon, hydrogen, oxygen, and nitrogen...
s that closely resemble those of another totally different protein, are also found in grains and legumes, as well as milk and dairy products. Advocates of the Paleolithic diet have argued that these components of agrarian diets promote vitamin and mineral deficiencies and may explain the development of the "diseases of civilization" as well as a number of autoimmune-related diseases
Autoimmune disease
Autoimmune diseases arise from an overactive immune response of the body against substances and tissues normally present in the body. In other words, the body actually attacks its own cells. The immune system mistakes some part of the body as a pathogen and attacks it. This may be restricted to...
.
Archeological record
One line of evidence used to support the Stone Age diet is the decline in human health and body mass that occurred with the adoption of agriculture, at the end of the Paleolithic era.Associated with the introduction of domesticated and processed plant foods, such as cereal grains, in the human diet, there was, in many areas, a general decrease in body stature and dentition size, and an increase in caries
Dental caries
Dental caries, also known as tooth decay or a cavity, is an irreversible infection usually bacterial in origin that causes demineralization of the hard tissues and destruction of the organic matter of the tooth, usually by production of acid by hydrolysis of the food debris accumulated on the...
rates. There is evidence of a general decline in health in some areas; whether the decline was caused by dietary change is debated academically.
Observational studies
Based on the subsistence patterns and biomarkerBiomarker (medicine)
In medicine, a biomarker is a term often used to refer to a protein measured in blood whose concentration reflects the severity or presence of some disease state...
s of hunter-gatherers studied in the last century, advocates argue that modern humans are well adapted to the diet of their Paleolithic ancestor.
The diet of modern hunter-gatherer groups is believed to be representative of patterns for humans of fifty to twenty-five thousand years ago, and individuals from these and other technologically primitive societies,
including those individuals who reach the age of 60 or beyond,
seem to be largely free of the signs and symptoms of chronic disease (such as obesity, high blood pressure, nonobstructive coronary atherosclerosis
Atherosclerosis
Atherosclerosis is a condition in which an artery wall thickens as a result of the accumulation of fatty materials such as cholesterol...
, and insulin resistance
Insulin resistance
Insulin resistance is a physiological condition where the natural hormone insulin becomes less effective at lowering blood sugars. The resulting increase in blood glucose may raise levels outside the normal range and cause adverse health effects, depending on dietary conditions. Certain cell types...
) that universally afflict the elderly in western societies (with the exception of osteoarthritis
Osteoarthritis
Osteoarthritis also known as degenerative arthritis or degenerative joint disease, is a group of mechanical abnormalities involving degradation of joints, including articular cartilage and subchondral bone. Symptoms may include joint pain, tenderness, stiffness, locking, and sometimes an effusion...
, which afflicts both populations).
Moreover, when these people adopt western diets, their health declines and they begin to exhibit signs and symptoms of "diseases of civilization
Lifestyle diseases
Lifestyle diseases are diseases that appear to increase in frequency as countries become more industrialized and people live longer...
". In one clinical study, stroke
Stroke
A stroke, previously known medically as a cerebrovascular accident , is the rapidly developing loss of brain function due to disturbance in the blood supply to the brain. This can be due to ischemia caused by blockage , or a hemorrhage...
and ischaemic heart disease
Ischaemic heart disease
Ischaemic or ischemic heart disease , or myocardial ischaemia, is a disease characterized by ischaemia of the heart muscle, usually due to coronary artery disease...
appeared to be absent in a population living on the island of Kitava
Trobriand Islands
The Trobriand Islands are a 450 km² archipelago of coral atolls off the eastern coast of New Guinea. They are situated in Milne Bay Province in Papua New Guinea. Most of the population of 12,000 indigenous inhabitants live on the main island of Kiriwina, which is also the location of the...
, in Papua New Guinea
Papua New Guinea
Papua New Guinea , officially the Independent State of Papua New Guinea, is a country in Oceania, occupying the eastern half of the island of New Guinea and numerous offshore islands...
, where a subsistence lifestyle, uninfluenced by western dietary habits
Western pattern diet
The Western pattern diet, also called Western dietary pattern or the meat-sweet diet, is a dietary habit chosen by many people in developed countries, and increasingly in developing countries. It is characterized by high intakes of red meat, sugary desserts, high-fat foods, and refined grains...
, was still maintained.
One of the most frequent criticisms of the Paleolithic diet is that it is unlikely that preagricultural hunter-gatherers suffered from the diseases of modern civilization
Lifestyle diseases
Lifestyle diseases are diseases that appear to increase in frequency as countries become more industrialized and people live longer...
simply because they did not live long enough to develop these illnesses, which are typically associated with old age.
According to S. Jay Olshansky
S. Jay Olshansky
Stuart Jay Olshansky is currently a Professor in the School of Public Health at the University of Illinois at Chicago and a Research Associate at the Center on Aging at the University of Chicago and at the London School of Hygiene and Tropical Medicine.-Biography:He received his Ph.D...
and Bruce Carnes, "there is neither convincing evidence nor scientific logic to support the claim that adherence to a Paleolithic diet provides a longevity benefit." In response to this argument, advocates of the paleodiet state that while Paleolithic hunter-gatherers did have a short average life expectancy, modern human populations with lifestyles resembling that of our preagricultural ancestors have little or no diseases of affluence
Diseases of affluence
Diseases of affluence is a term sometimes given to selected diseases and other health conditions which are commonly thought to be a result of increasing wealth in a society...
, despite sufficient numbers of elderly.
In hunter-gatherer societies where demographic data is available, the elderly are present, but they tend to have high mortality rates and rarely survive past the age of 80, with causes of death (when known) ranging from injuries to measles and tuberculosis.
Critics further contend that food energy excess, rather than the consumption of specific novel foods, such as grains and dairy products, underlies the diseases of affluence. According to Geoffrey Cannon, science and health policy advisor to the World Cancer Research Fund
World Cancer Research Fund
World Cancer Research Fund International is a not-for-profit association, established by royal decree in Belgium, with headquarters in London, UK...
, humans are designed to work hard physically to produce food for subsistence and to survive periods of acute food shortage
Famine
A famine is a widespread scarcity of food, caused by several factors including crop failure, overpopulation, or government policies. This phenomenon is usually accompanied or followed by regional malnutrition, starvation, epidemic, and increased mortality. Every continent in the world has...
, and are not adapted to a diet rich in energy-dense foods.
Similarly, William R. Leonard, a professor of anthropology at Northwestern University
Northwestern University
Northwestern University is a private research university in Evanston and Chicago, Illinois, USA. Northwestern has eleven undergraduate, graduate, and professional schools offering 124 undergraduate degrees and 145 graduate and professional degrees....
, states that the health problems facing industrial societies stem not from deviations from a specific ancestral diet but from an imbalance between calories consumed and calories burned, a state of energy excess uncharacteristic of ancestral lifestyles.
Intervention studies
The first animal experiment on a Paleolithic diet suggested that this diet, as compared with a cereal-based diet, conferred higher insulin sensitivityInsulin resistance
Insulin resistance is a physiological condition where the natural hormone insulin becomes less effective at lowering blood sugars. The resulting increase in blood glucose may raise levels outside the normal range and cause adverse health effects, depending on dietary conditions. Certain cell types...
, lower C-reactive protein
C-reactive protein
C-reactive protein is a protein found in the blood, the levels of which rise in response to inflammation...
and lower blood pressure
Blood pressure
Blood pressure is the pressure exerted by circulating blood upon the walls of blood vessels, and is one of the principal vital signs. When used without further specification, "blood pressure" usually refers to the arterial pressure of the systemic circulation. During each heartbeat, BP varies...
in 24 domestic pigs.
There was no difference in basal serum glucose. The first human clinical randomized controlled trial
Randomized controlled trial
A randomized controlled trial is a type of scientific experiment - a form of clinical trial - most commonly used in testing the safety and efficacy or effectiveness of healthcare services or health technologies A randomized controlled trial (RCT) is a type of scientific experiment - a form of...
involved 29 people with glucose intolerance and ischemic heart disease, and it found that those on a Paleolithic diet had a greater improvement in glucose tolerance compared to those on a Mediterranean diet
Mediterranean diet
The Mediterranean diet is a modern nutritional recommendation inspired by the traditional dietary patterns of southern Italy, Crete and much of the rest of Greece in the 1960s....
.
Furthermore, the Paleolithic diet was found to be more satiating per calorie compared to the Mediterranean diet.
A clinical, randomized, controlled cross-over study in the primary care
Primary care
Primary care is the term for the health services by providers who act as the principal point of consultation for patients within a health care system...
setting compared the Paleolithic diet with a commonly prescribed diet for type 2 diabetes. The Paleolithic diet resulted in lower mean values of HbA1c, triacylglycerol, diastolic blood pressure, body mass index
Body mass index
The body mass index , or Quetelet index, is a heuristic proxy for human body fat based on an individual's weight and height. BMI does not actually measure the percentage of body fat. It was invented between 1830 and 1850 by the Belgian polymath Adolphe Quetelet during the course of developing...
, waist circumference and higher values of high density lipoprotein
High density lipoprotein
High-density lipoprotein is one of the five major groups of lipoproteins, which, in order of sizes, largest to smallest, are chylomicrons, VLDL, IDL, LDL, and HDL, which enable lipids like cholesterol and triglycerides to be transported within the water-based bloodstream...
when compared to the Diabetes diet. Also, glycemic control and other cardiovascular factors were improved in both diets without significant differences. It is also important to note that the Paleolithic diet was lower in total energy, energy density, carbohydrate, dietary glycemic load and glycemic index, saturated fatty acids and calcium, but higher in unsaturated fatty acids, dietary cholesterol and some vitamins.
Two clinical trials designed to test various physiological effects of the Paleolithic diet are currently underway,
and the results of one completed trial
have shown metabolic and physiologic improvements. The European Journal of Clinical Nutrition published a study
of a trial of the Paleolithic diet in 20 healthy volunteers. In the study, in three weeks there was an average weight reduction of 2.3 kg, an average reduction in waist circumference of 1.5 cm (about one-half inch), an average reduction in systolic blood pressure of 3 mm Hg, and a 72% reduction in plasminogen activator inhibitor-1 (which might translate into a reduced risk of heart attack and stroke.)
However, the NHS
National Health Service (England)
The National Health Service or NHS is the publicly funded healthcare system in England. It is both the largest and oldest single-payer healthcare system in the world. It is able to function in the way that it does because it is primarily funded through the general taxation system, similar to how...
Knowledge Service pointed out that this study, like most human diet studies, relied on observational data.
Sustainability
The Paleolithic diet has been criticized on the grounds that it cannot be implemented on a worldwide scale.According to Loren Cordain
Loren Cordain
Loren Cordain is an American scientist who specializes in fields of nutrition and exercise physiology. He is notable as an advocate of the paleolithic diet and a researcher into paleolithic nutrition; he wrote numerous peer-reviewed articles on the subject, as well as several popular books, most...
, if such a diet was widely adopted, it would compromise the food security
Food security
Food security refers to the availability of food and one's access to it. A household is considered food-secure when its occupants do not live in hunger or fear of starvation. According to the World Resources Institute, global per capita food production has been increasing substantially for the past...
of populations dependent on cereal grains for their subsistence. However, he says that where cereals are not a necessity, as in most western countries, reverting to a grain-free diet can be highly practical in terms of cutting long-term health care costs
Health economics
Health economics is a branch of economics concerned with issues related to efficiency, effectiveness, value and behavior in the production and consumption of health and health care...
.
Barry Bogin
Barry Bogin
Barry Bagel Bogin is an American physical anthropologist trained at Temple University that researches physical growth in Guatemalan Maya children, and is a theorist upon the evolutionary origins of human childhood. He is presently at Loughborough University in the UK, after professorships at the...
, a professor of anthropology
Anthropology
Anthropology is the study of humanity. It has origins in the humanities, the natural sciences, and the social sciences. The term "anthropology" is from the Greek anthrōpos , "man", understood to mean mankind or humanity, and -logia , "discourse" or "study", and was first used in 1501 by German...
at the University of Michigan
University of Michigan
The University of Michigan is a public research university located in Ann Arbor, Michigan in the United States. It is the state's oldest university and the flagship campus of the University of Michigan...
, states that less intensive farming techniques, such as pasture-grazed cattle
Cattle feeding
Different cattle feeding production systems have separate advantages and disadvantages. Most cows have a diet that is composed of at least some forage . In fact most beef cattle are raised on pasture from birth in the spring until autumn...
, will not produce sufficient meat to feed the world’s population
Population
A population is all the organisms that both belong to the same group or species and live in the same geographical area. The area that is used to define a sexual population is such that inter-breeding is possible between any pair within the area and more probable than cross-breeding with individuals...
.
On another level, critics have argued that "exclusion diets" such as the Stone Age diet "can be highly restrictive, socially disruptive, and expensive."
See also
- AnopsologyAnopsologyAnopsology a nutritional theory outlined in 1964 by Guy-Claude Burger. It led to a raw food diet based on the evolution theory and the assumption of the existence of a nutritional instinct, capable of adjusting food intake to nutritional needs via sensory pleasure...
- BushfoodBushfoodBushfood traditionally relates to any food native to Australia and used as sustenance by the original inhabitants, the Australian Aborigines, but it is a reference to any native fauna/flora that is used for culinary and/or medicinal purposes regardless of which continent or culture it originates...
- Diabetic dietDiabetic dietThere is much controversy regarding what diet to recommend to sufferers of diabetes mellitus. The diet most often recommended is high in dietary fiber, especially soluble fiber, but low in fat . Recommendations of the fraction of total calories to be obtained from carbohydrate intake range from 1/6...
- Inuit dietInuit dietInuit consume a diet of foods that are fished, hunted, and gathered locally. This may include walrus, Ringed Seal, Bearded Seal, beluga whale, caribou, polar bear, muskoxen, birds and fish. While it is not possible to cultivate plants for food in the Arctic the Inuit have traditionally gathered...
- Mark SissonMark SissonMark Sisson is an American fitness author and blogger, and a former distance runner, triathlete and Ironman competitor. Sisson finished 4th in the February 1982 Ironman World Championship. He has written several books, including The Primal Blueprint, which is based on the paleolithic diet. The...
- Natural foods
- Nutritional genomicsNutritional genomicsNutritional genomics is a science studying the relationship between human genome, nutrition and health.It can be divided into two disciplines:*Nutrigenomics: studies the effect of nutrients on health through altering genome, proteome, metabolome and the resulting changes in...
- Paleolithic lifestylePaleolithic lifestyleA paleolithic lifestyle refers to living as humans did in the paleolithic era , or attempting to recreate such a lifestyle in the present day. The rationale for such an approach is that humans have evolved for millions of years in a paleolithic environment...
- Peter UngarPeter UngarPeter S. Ungar is an American paleoanthropologist and evolutionary biologist. He is Distinguished Professor and Chairman of Anthropology at the University of Arkansas. Before arriving at Arkansas he taught at the Johns Hopkins School of Medicine and the Duke University Medical Center.Ungar is...
- Prehistoric medicinePrehistoric medicinePrehistoric medicine is a term used to describe the use of medicine before the invention of writing. As the timing of the invention of writing varies per culture and region, the term "prehistoric medicine" encompasses a wide range of time periods and dates....
- Protein poisoning
- Raw feedingRaw feedingRaw feeding is the practice of feeding domestic dogs, cats and other animals a diet primarily of uncooked meat, edible bones, and organs.*Supporters of raw feeding believe that the natural diet of raw meat, bones, and organs is superior nutritionally to highly processed commercial pet food...
- Ray MearsRay MearsRaymond Paul "Ray" Mears is an English woodsman, instructor, author and TV presenter. His TV appearances cover bushcraft and survival techniques, and he is best known for the TV series Ray Mears' Bushcraft, Ray Mears' World of Survival, Extreme Survival, Survival with Ray Mears, Wild Britain with...
- Roger MacDougallRoger MacDougallRoger MacDougall was a Scottish playwright.MacDougall began writing the occasional screenplay in the late 30s, working both alone and in collaboration with others. Most of his plays were produced during the 50s...
- Vilhjalmur StefanssonVilhjalmur StefanssonVilhjalmur Stefansson was a Canadian Arctic explorer and ethnologist.-Early life:Stefansson, born William Stephenson, was born at Gimli, Manitoba, Canada, in 1879. His parents had emigrated from Iceland to Manitoba two years earlier...
- Whole foodsWhole foodsWhole foods are foods that are unprocessed and unrefined, or processed and refined as little as possible, before being consumed. Whole foods typically do not contain added ingredients, such as salt, carbohydrates, or fat. Examples of whole foods include unpolished grains, beans, fruits, vegetables...