Zone diet
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The Zone diet is a diet popularized in books by biochemist Barry Sears. It advocates consuming calories from carbohydrates, protein and fat in a fixed ratio.[1]
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[edit] Theory
The diet centers on a "40:30:30" ratio of calories obtained daily from carbohydrates, proteins, and fats, 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.[citation needed] The Scientific American Frontiers study compared the effectiveness of several popular 'diet' regimes 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.[citation needed] Participants also reported the Zone as the easiest regime to adjust to, i.e. having the fewest adverse affects such as fatigue or hunger.[citation needed] 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 is more efficient and does not have to store excess calories as fat. The human body cannot store fat and burn fat at the same time[citation needed], 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.[citation needed] 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 popularized the taking of pharmaceutical-grade Omega 3 fish oils.[2]
[edit] Hormonal paradoxes
Sears believes in a hormonal paradox contrary to the "low-fat" rationale of most diets, claiming that low-fat diets increase the production of the hormone insulin, causing the body to store more fat. The example proposed by him is the cattle ranching practice of fattening livestock efficiently by feeding them lots of low-fat grain. However this is due to the amount of the grain, and thus the total amount of calories consumed, being large. He and others also point out the supposed irony that human diets in the West for the last twenty years have been full of low-fat carbohydrates, yet people are considered more obese now.
Additionally, Sears suggests fat consumption is essential for "burning" fat.
His rationale is: Monounsaturated fats 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 nonstarchy 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."
[edit] Comparison to low-carb diets
The Zone is considered a low-carb diet.[3] It is not as restrictive in total carbohydrate intake as some of the other low-carbohydrate diets (e.g. the Atkins diet) that became extremely popular throughout the United States in 2003 and 2004. Sears claims these other diets miss the point. According to him, they ignore the importance of hormonal balance, as well as the influence of dietary balance on digestion and hormone production.
[edit] Specific cases
[edit] Italy
The introduction of the Zone in Italy was due to Eddy Ottoz's work.
[edit] Famous obesity case
Possibly the most famous case of someone using the diet effectively has been Manuel Uribe. After weighing in at around 560 kg (1234 lbs or over 88 stone) but within 2 years had lost about 184 kg. (Now he weighs 376 kg).[4] 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[citation needed], 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 sceptical 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.[5]
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.[citation needed]
Despite his weight, Dr. Sears considers Manuel one of the healthiest men in Mexico. He does not have diabetes, and his blood pressure and triglyceride levels are normal. In addition, his resting heart rate averages 62 beats per minute,[citation needed] a level usually found in trained athletes. Even though Manuel is confined to his bed, his medical team designed a tailored exercise regimen that includes sit-ups, pull-ups and hand-biking to help build muscle mass and accelerate fat loss.[citation needed]
[edit] Famous followers
Several Hollywood stars, including Jennifer Aniston, Renee Zellweger, Cindy Crawford, Charlie Sheen, Tiger Woods, and Tom Cruise in addition to Levi Leipheimer are believed to have followed the Zone diet.
[edit] Criticism
The American Heart Association does not recommend the Zone Diet due to high protein, lack of essential nutrients, and little information on long-term effects.[6] However, Sears believes the characterization of the Zone diet as 'high-protein' is inaccurate. 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.
Most vegetarian or vegan diets, according to Sears, are highly dissimilar from The Zone because they generally utilize very little protein relative to carbohydrate consumption. This, says Sears, prohibits the body from operating truly efficiently. As critical as Sears is of vegetarian and vegan diets, individuals who promote a vegetarian diet are also very critical of aspects of the Zone and similar diets. In 2000 Dr. Sears published the Soy Zone where he outlined a zone diet based around soy protein, making it more vegetarian-friendly.
Other 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.[7]
[edit] Official Zone books
(Partial list)
- Sears, Barry (1995). The Zone: A Dietary Road Map. HarperCollins Publishers. ISBN 0060987065. Sears's initial book on the Zone diet.
- Sears, Barry (1997). Mastering the Zone. HarperCollins Publishers. ISBN 006101124X. Sears urges substitution of raw vegetables for pastas, breads and refined sugars. More diagrams and flowcharts than in The Zone.
- Sears, Barry (1999). The Anti-Aging Zone. Regan Books. ISBN 0060392436. Information on meditation, relaxation and exercise in addition to diet.
- Sears, Barry; Kotz, Deborah (2000). A Week in the Zone: A Quick Course in the Healthiest Diet for You. Regan Books. ISBN 0060741902.
- Sears, Barry (2000). The Soy Zone. Regan Books. ISBN 0060393106. 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.
- Sears, Barry (2002). The Omega Rx Zone: The Miracle of the New High-Dose Fish Oil. Regan Books. ISBN 0060393130. 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.
- Sears, Barry (2005). The Anti-Inflammation Zone: Reversing the Silent Epidemic That's Destroying Our Health. Regan Books. ISBN 0060834145.
[edit] See also
[edit] References
- ^ FOXNews.com - Mexico's 'Half-Ton Man' Sheds Nearly 400 Poundsgenerated title -->
- ^ Amazon.com: The Anti-Inflammation Zone: Reversing the Silent Epidemic That's Destroying Our Health: Books: Barry Sears
- ^ Anne Collins - Short Review of Barry Sears Zone High Protein Low Carb Weight Loss Diet Program Retrieved on October 25, 2007.
- ^ "Manuel Uribe". http://www.manueluribe.com/manuel/. Retrieved on 2008-07-15.
- ^ citation needed
- ^ High-Protein Diets
- ^ The Zone Diet
