Zone diet
Encyclopedia
The Zone diet is a diet
popularized in books by biochemist
Barry Sears
. It advocates consuming calories from carbohydrates, protein, and fat in a balanced ratio.
s, protein
s, and fat
s, respectively. The ideal formula has been under debate, although studies over the past several years (including a non-scientific study by the PBS
documentary show Scientific American Frontiers
) have shown that it can produce weight loss at reasonable rates. The Scientific American Frontiers study compared the effectiveness of several popular 'diet' regimens including the Zone; somewhat to the surprise of the show's staff, the participants on the Zone experienced the greatest fat loss while simultaneously gaining muscle mass. Participants also reported the Zone as the easiest regime to adjust to, i.e., having the fewest adverse affects such as fatigue or hunger. Most people who report fatigue find that the fatigue diminishes by day 2 or 3.
"The Zone" is Sears' term for proper hormone
balance. When insulin
levels are neither too high nor too low and glucagon
levels are not too high, then specific anti-inflammatory chemicals (types of eicosanoids) are released, which have similar effects to aspirin
, but without downsides such as gastric bleeding. Sears claims that a 30:40 ratio of protein to carbohydrates triggers this effect, and this is called 'The Zone.' Sears claims that these natural anti-inflammatories are heart- and health-friendly. There is no evidence that eating in this way affects hormone levels.
Additionally, the human body in caloric balance does not have to store excess calories as fat
. The human body cannot store fat and burn fat at the same time, and Sears believes it takes time (significant time if insulin levels were high because of unbalanced eating) to switch from the former to the latter. Using stored fat for energy causes weight loss.
Another key feature of the Zone diet, introduced in his later books, is an intake of a particular ratio of Omega-3 to Omega-6 fatty acids. Dr. Sears is believed to have popularised the taking of pharmaceutical-grade Omega 3 fish oils.
). He claims that the relatively high proportion of carbohydrate in these diets—by comparison to protein— increases the production of the hormone insulin, causing the body to store more fat. The example proposed by Sears is the cattle
ranching practice of fattening livestock efficiently by feeding them high amounts of high-carbohydrate grain. However, excess fat gains can be attributable to the amount of the grain and thus the total amount of calories consumed. Sears also points out the supposed irony:
Additionally, Sears suggests fat consumption is essential for "burning" fat. His rationale is: Monounsaturated fat
s in a meal contribute to a feeling of fullness and decrease the rate at which carbohydrates are absorbed into the bloodstream. Slower carbohydrate absorption means lower insulin levels which means less stored fat and a faster transition to fat burning. If the body needs energy and can't burn fat because of high insulin levels, a person feels tired as their brain starves and metabolism slows to compensate. This occurs because the brain runs on glucose
and high insulin levels deplete blood glucose levels. Such a condition, rebound hypoglycemia
, causes sweet cravings (which just starts the high-insulin cycle all over again).
Sears describes a Zone meal as follows: "Eat as much protein as the palm of your hand, as much non-starchy raw vegetables as you can stand for the vitamins, enough carbohydrates to maintain mental clarity because the brain runs on glucose, and enough monounsaturated oils to keep feelings of hunger away."
is a matter of opinion and definition. It is much less restrictive in total carbohydrate intake than the Atkins diet
that became extremely popular throughout the United States
in 2003 and 2004. Sears claims that diets specifically designed as "low carb" miss the point. According to him, they ignore the importance of moderation and balance: hormonal balance, as well as the influence of dietary balance on digestion
and hormone production. A reasonable argument could be made that the typical American follows a
"high carb" diet, and that the Zone diet is simply a moderate one.
. After weighing in at around 560 kg (1234 lbs or over 88 stone
), he had lost about 184 kg within 2 years (he now weighs 376 kg).
After decades of failed weight-loss methods, including a botched liposuction that nearly killed him, Uribe believes devotion to the Zone Diet has been the only weight-loss program to have such a positive impact on him. Dr. Barry Sears, along with two of Mexico's most prestigious physicians , Dr. Silvia Orozco Avina and Dr. Gustavo Orozco Avina, are at the helm of the interdisciplinary team of doctors, nutritionists and exercise physiologists who continue to work diligently to help Manuel reach his goal. Aside from Dr. Sears, the other physicians on the team are more skeptical of Uribe's use of the Zone diet, but feel that if it helps Manuel stick to a diet and lose weight, they will tolerate his use of it.
Manuel's current diet consists of about 2,000 calories per day broken up into six meals. His specially-designed menu includes a wide variety of meals including egg-white omelets, fresh salads, chicken fajitas and fish filet in a bed of spring greens. In fact, Manuel's biggest problem is not lack of appetite control, but eating all the food he is supposed to eat.
The most common vegetarian or vegan diets, according to Sears, are highly dissimilar from The Zone because they generally utilize very little protein relative to carbohydrate consumption. Low-protein vegetarian diets, says Sears, prohibits the body from operating truly efficiently. As critical as Sears has been of what he calls typical vegetarian and vegan diets, vegetarians who promote low-protein diets have also been very critical of aspects of the Zone and similar diets. In 2000, Sears published the Soy Zone where he outlined a zone diet based around soy protein
and soy
foods, for vegetarians
who wish to follow a Zone diet.
Some nutritional experts, including some of Sears' former colleagues, are critical of his conclusions from the scientific evidence, contending that he has distorted or exaggerated the meaning of much of the basic research. They point out that no direct studies to verify his conclusions have been performed.
Dieting
Dieting is the practice of eating food in a regulated fashion to achieve or maintain a controlled weight. In most cases dieting is used in combination with physical exercise to lose weight in those who are overweight or obese. Some athletes, however, follow a diet to gain weight...
popularized in books by biochemist
Biochemist
Biochemists are scientists who are trained in biochemistry. Typical biochemists study chemical processes and chemical transformations in living organisms. The prefix of "bio" in "biochemist" can be understood as a fusion of "biological chemist."-Role:...
Barry Sears
Barry Sears
Barry Sears, Ph.D. is a biochemist best known for creating and promoting the Zone diet, which is aimed at achieving stable blood sugar levels, hormonal balance, low inflammation, and good health...
. It advocates consuming calories from carbohydrates, protein, and fat in a balanced ratio.
Theory
The diet centers on a "40:30:30" ratio of calories obtained daily from carbohydrateCarbohydrate
A carbohydrate is an organic compound with the empirical formula ; that is, consists only of carbon, hydrogen, and oxygen, with a hydrogen:oxygen atom ratio of 2:1 . However, there are exceptions to this. One common example would be deoxyribose, a component of DNA, which has the empirical...
s, protein
Protein
Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...
s, and fat
Fat
Fats consist of a wide group of compounds that are generally soluble in organic solvents and generally insoluble in water. Chemically, fats are triglycerides, triesters of glycerol and any of several fatty acids. Fats may be either solid or liquid at room temperature, depending on their structure...
s, respectively. The ideal formula has been under debate, although studies over the past several years (including a non-scientific study by the PBS
Public Broadcasting Service
The Public Broadcasting Service is an American non-profit public broadcasting television network with 354 member TV stations in the United States which hold collective ownership. Its headquarters is in Arlington, Virginia....
documentary show Scientific American Frontiers
Scientific American Frontiers
Scientific American Frontiers was an American television program primarily focused on informing the public about new technologies and discoveries in science and medicine. It was a companion program to the Scientific American magazine. The show was produced for PBS in the U.S...
) have shown that it can produce weight loss at reasonable rates. The Scientific American Frontiers study compared the effectiveness of several popular 'diet' regimens including the Zone; somewhat to the surprise of the show's staff, the participants on the Zone experienced the greatest fat loss while simultaneously gaining muscle mass. Participants also reported the Zone as the easiest regime to adjust to, i.e., having the fewest adverse affects such as fatigue or hunger. Most people who report fatigue find that the fatigue diminishes by day 2 or 3.
"The Zone" is Sears' term for proper hormone
Hormone
A hormone is a chemical released by a cell or a gland in one part of the body that sends out messages that affect cells in other parts of the organism. Only a small amount of hormone is required to alter cell metabolism. In essence, it is a chemical messenger that transports a signal from one...
balance. When 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....
levels are neither too high nor too low and glucagon
Glucagon
Glucagon, a hormone secreted by the pancreas, raises blood glucose levels. Its effect is opposite that of insulin, which lowers blood glucose levels. The pancreas releases glucagon when blood sugar levels fall too low. Glucagon causes the liver to convert stored glycogen into glucose, which is...
levels are not too high, then specific anti-inflammatory chemicals (types of eicosanoids) are released, which have similar effects to aspirin
Aspirin
Aspirin , also known as acetylsalicylic acid , is a salicylate drug, often used as an analgesic to relieve minor aches and pains, as an antipyretic to reduce fever, and as an anti-inflammatory medication. It was discovered by Arthur Eichengrun, a chemist with the German company Bayer...
, but without downsides such as gastric bleeding. Sears claims that a 30:40 ratio of protein to carbohydrates triggers this effect, and this is called 'The Zone.' Sears claims that these natural anti-inflammatories are heart- and health-friendly. There is no evidence that eating in this way affects hormone levels.
Additionally, the human body in caloric balance does not have to store excess calories as fat
Fat
Fats consist of a wide group of compounds that are generally soluble in organic solvents and generally insoluble in water. Chemically, fats are triglycerides, triesters of glycerol and any of several fatty acids. Fats may be either solid or liquid at room temperature, depending on their structure...
. The human body cannot store fat and burn fat at the same time, and Sears believes it takes time (significant time if insulin levels were high because of unbalanced eating) to switch from the former to the latter. Using stored fat for energy causes weight loss.
Another key feature of the Zone diet, introduced in his later books, is an intake of a particular ratio of Omega-3 to Omega-6 fatty acids. Dr. Sears is believed to have popularised the taking of pharmaceutical-grade Omega 3 fish oils.
Hormonal paradoxes
Sears believes in a hormonal paradox contrary to the "low-fat/high carbohydrate" rationale of most diets (including the USDA "Food Pyramid"Food guide pyramid
A food guide pyramid is a triangular or pyramid-shaped nutrition guide divided into sections to show the recommended intake for each food group. The first food pyramid was published in Sweden in 1974. The most widely known food pyramid was introduced by the United States Department of Agriculture...
). He claims that the relatively high proportion of carbohydrate in these diets—by comparison to protein— increases the production of the hormone insulin, causing the body to store more fat. The example proposed by Sears is the cattle
Cattle
Cattle are the most common type of large domesticated ungulates. They are a prominent modern member of the subfamily Bovinae, are the most widespread species of the genus Bos, and are most commonly classified collectively as Bos primigenius...
ranching practice of fattening livestock efficiently by feeding them high amounts of high-carbohydrate grain. However, excess fat gains can be attributable to the amount of the grain and thus the total amount of calories consumed. Sears also points out the supposed irony:
"data analysis ... shows that in spite of the fact that the American public has dramatically cut back on the amount of fat consumed, the country has experienced an epidemic rise in obesity."
Additionally, Sears suggests fat consumption is essential for "burning" fat. His rationale is: Monounsaturated fat
Monounsaturated 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...
s in a meal contribute to a feeling of fullness and decrease the rate at which carbohydrates are absorbed into the bloodstream. Slower carbohydrate absorption means lower insulin levels which means less stored fat and a faster transition to fat burning. If the body needs energy and can't burn fat because of high insulin levels, a person feels tired as their brain starves and metabolism slows to compensate. This occurs because the brain runs on glucose
Glucose
Glucose is a simple sugar and an important carbohydrate in biology. Cells use it as the primary source of energy and a metabolic intermediate...
and high insulin levels deplete blood glucose levels. Such a condition, rebound hypoglycemia
Hypoglycemia
Hypoglycemia or hypoglycæmia is the medical term for a state produced by a lower than normal level of blood glucose. The term literally means "under-sweet blood"...
, causes sweet cravings (which just starts the high-insulin cycle all over again).
Sears describes a Zone meal as follows: "Eat as much protein as the palm of your hand, as much non-starchy raw vegetables as you can stand for the vitamins, enough carbohydrates to maintain mental clarity because the brain runs on glucose, and enough monounsaturated oils to keep feelings of hunger away."
Comparison to low-carb diets
Whether the Zone diet is a low-carb dietLow-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...
is a matter of opinion and definition. It is much less restrictive in total carbohydrate intake than the Atkins diet
Atkins Nutritional Approach
The Atkins diet, officially called the Atkins Nutritional Approach, is a low-carbohydrate diet created by Robert Atkins from a research paper he read in the Journal of the American Medical Association published by Gordon Azar and Walter Lyons Bloom. Atkins stated that he used the study to resolve...
that became extremely popular throughout the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
in 2003 and 2004. Sears claims that diets specifically designed as "low carb" miss the point. According to him, they ignore the importance of moderation and balance: hormonal balance, as well as the influence of dietary balance on digestion
Digestion
Digestion is the mechanical and chemical breakdown of food into smaller components that are more easily absorbed into a blood stream, for instance. Digestion is a form of catabolism: a breakdown of large food molecules to smaller ones....
and hormone production. A reasonable argument could be made that the typical American follows a
"high carb" diet, and that the Zone diet is simply a moderate one.
Famous obesity case
Possibly the most famous case of someone using the diet effectively has been Manuel UribeManuel Uribe Garza
Manuel "Xavier" Uribe is a man from Monterrey, Nuevo León, Mexico, notable for suffering from morbid obesity to one of the greatest extents known in recorded history...
. After weighing in at around 560 kg (1234 lbs or over 88 stone
Stone (weight)
The stone is a units of measurement that was used in many North European countries until the advent of metrication. It value, which ranged from 3 kg to 12 kg, varied from city to city and also often from commodity to commodity...
), he had lost about 184 kg within 2 years (he now weighs 376 kg).
After decades of failed weight-loss methods, including a botched liposuction that nearly killed him, Uribe believes devotion to the Zone Diet has been the only weight-loss program to have such a positive impact on him. Dr. Barry Sears, along with two of Mexico's most prestigious physicians , Dr. Silvia Orozco Avina and Dr. Gustavo Orozco Avina, are at the helm of the interdisciplinary team of doctors, nutritionists and exercise physiologists who continue to work diligently to help Manuel reach his goal. Aside from Dr. Sears, the other physicians on the team are more skeptical of Uribe's use of the Zone diet, but feel that if it helps Manuel stick to a diet and lose weight, they will tolerate his use of it.
Manuel's current diet consists of about 2,000 calories per day broken up into six meals. His specially-designed menu includes a wide variety of meals including egg-white omelets, fresh salads, chicken fajitas and fish filet in a bed of spring greens. In fact, Manuel's biggest problem is not lack of appetite control, but eating all the food he is supposed to eat.
Criticism
The recommended protein intake, taken as meat, is a significant source of saturated fat. However, Sears believes the characterization of the Zone diet as 'high-protein' is inaccurate, as more calories come from carbohydrates than protein. In his book, he advocates a formula based on lean body mass and activity level to determine the appropriate daily intake of protein. For example, a female of average height and average build who has a moderately active lifestyle is encouraged to eat around 60g of protein daily.The most common vegetarian or vegan diets, according to Sears, are highly dissimilar from The Zone because they generally utilize very little protein relative to carbohydrate consumption. Low-protein vegetarian diets, says Sears, prohibits the body from operating truly efficiently. As critical as Sears has been of what he calls typical vegetarian and vegan diets, vegetarians who promote low-protein diets have also been very critical of aspects of the Zone and similar diets. In 2000, Sears published the Soy Zone where he outlined a zone diet based around soy protein
Soy protein
Soy protein is a protein that is isolated from soybean. It is made from dehulled, defatted soybean meal. Dehulled and defatted soybeans are processed into three kinds of high protein commercial products : soy flour, concentrates, and isolates. Soy protein isolate has been used since 1959 in foods ...
and soy
Soybean
The soybean or soya bean is a species of legume native to East Asia, widely grown for its edible bean which has numerous uses...
foods, for vegetarians
Vegetarianism
Vegetarianism encompasses the practice of following plant-based diets , with or without the inclusion of dairy products or eggs, and with the exclusion of meat...
who wish to follow a Zone diet.
Some nutritional experts, including some of Sears' former colleagues, are critical of his conclusions from the scientific evidence, contending that he has distorted or exaggerated the meaning of much of the basic research. They point out that no direct studies to verify his conclusions have been performed.
Official Zone books
Sears's initial book on the Zone diet. Sears urges substitution of raw vegetables for pastas, breads and refined sugars. More diagrams and flowcharts than in The Zone. Information on meditation, relaxation and exercise in addition to diet. Discusses Sears preference for soy protein as part of his balanced eating program. "The longest-living people in the world" living in Okinawa, Japan consume much greater amounts of soy protein and eat smaller meals than most other people. Discusses "high-dose fish oil;" a newly-introduced invented pharmaceutical-grade fish oil that Sears touts as a medical miracle that will put the eicasonids in balance and reduce inflammation. Extra virgin olive oil is also promoted for its phytochemicals.See also
- Diet (nutrition)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...
- List of diets
- Medical research related to low-carbohydrate dietsMedical research related to low-carbohydrate dietsLow-carbohydrate diets became a major weight loss and health maintenance trend during the late 1990s and early 2000s. While their popularity has waned recently from its peak, they remain popular. This diet trend has stirred major controversies in the medical and nutritional sciences communities...
- Online weight loss plansOnline weight loss plansOnline weight loss plans are web-based fitness programs designed to help participants lose weight. They usually include assistance in the areas necessary for weight loss. For example, weight loss information, goal setting, progress tracking, meal and workout planning, and personal support from...
External links
- Official Website of the Zone Diet
- Dr. Barry Sears' Official Website
- History of the Zone Diet
- The Zone Diet Explained – Synopsis of the Zone Diet with pictures of example meals, charts for finding your Zone requirements, and charts with Zone content of most foods.