Zone Diet
Overview:
Proponents of the Zone diet recommend a diet consisting of lean proteins and naturally occuring carbohydrates (like those found in high-fiber vegetables and fruit.) The Zone diet recommends that you consume 40 percent of your calories from carbohydrates, 30 percent from protein and 30 percent from fat (the so-called 40:30:30 proportions).
The Zone diet is said to work for two reasons:
1. Adherents reduce their overall caloric intake;
2. A dramatic reduction in caloric intake (because of fasting or beginning a low-calorie diet) often causes your body to go into "survival" mode. Your body will actually begin to conserve energy and burn fewer calories while you rest. (Referred to in the literature as a low basal metabolic rate <http://www.dietcompare.com/definitions/basal_rate.html>). However, the 40:30:30 combination of food proposed by the Zone diet prevents the body from thinking that it has begun to starve, thus your basal rate does not decline.
The Zone Diet Details
The program is detailed in the book The Zone: Revolutionary Life Plan to Put Your Body in Total Balance for Permanent Weight Loss by Dr. Barry Sears. Balance is the key focus of Sears' plan; more specifically, the balancing of the correct ratio of carbs, fat, and protein is key.
Dr. Sears suggests that by consuming the right amounts of these components, you can control your body's insulin production. Sears says that when your insulin is at the right level, your body burns fat more effectively. There is also a concentration on avoiding "bad" carbohydrates whenever possible.
The Zone's food plan consists of 40% of your daily caloric intake in the form of carbohydrate, 30% of protein, with fat making up the final 30%. The book provides a "dietary roadmap" to The Zone, in which you learn the components -- or "blocks" as Sears refers to them -- of your weight loss program. Pay close attention to this part: The roadmap will be your eating guide for the duration of the time you spend in The Zone.
Who created the diet?
Dr. Barry Sears introduced the diet in his book Enter the Zone, published in 1995.
Medical Studies
In a 2001 study, Dr. Donald Layman (University of Illinois, Urbana-Champlain) placed 12 middle-aged overweight women on a 1660 calories per day diet consistent with the USDA's Food Guide Pyramid. He placed 12 other middle- aged overweight women on a 1660 calorie diet consistent with the Zone diet. After 10 weeks, those on the Zone-equivalent diet lost slightly more weight (16.5 vs 15 pounds) but the real story was in the makeup of the weight loss. Those on the Zone-equivalent diet lost 27% less muscle and 18% more body fat than those following the USDA-equivalent diet. In addition, the study reported evidence that the women on the Zone-equivalent diet burned more calories while resting.
A 1999 study led by Dr. David Ludwig found that patients following a high- carbohydrate diet (perhaps more accurately, a high glycemic index http://www.dietcompare.com/definitions/glycemic_index.html diet) burned fewer calories at rest than did those who followed a roughly Zone- equivalent diet.
Additional Resources:
Enter the Zone, Barry Sears, MD. (1995)
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