The Zone Diet, outlined by Dr. Barry Sears in the bestselling book "Enter the Zone," is a low-carb diet based on the concept that controlling blood sugar promotes weight loss. The Zone diet encourages the use of its own brand of omega-3 and polyphenol supplements, and purports to help you burn fat faster and improve your health. Success on the Zone Diet, as with any diet, depends on whether the food choices suit your taste and how long you maintain the diet. Consult with your doctor before starting a weight-loss program, particularly if you have a history of heart problems or diet-related illnesses.
Nutrient Composition
The Zone Diet features a 40-30-30 eating plan, meaning that 40 percent of your calories come from carbohydrates, and that protein and fat each contribute 30 percent of overall calories. Although the fat intake on the Zone Diet aligns with established nutritional guidelines, the carbohydrate intake is significantly lower -- 40 percent compared to a recommended average of 55 percent -- and the protein intake is slightly higher -- 30 percent compared to the recommended average of 15 percent.
Claims
At the core of the Zone Diet is the suggestion that changes in the composition of your diet over time lead to inflammation and disrupt hormonal communication, which contributes to overweight and obesity. The goal of the diet is to reduce inflammation and restore hormonal communication by promoting the consumption of adequate amounts of protein and reducing carbohydrate intake, which theoretically keeps insulin levels in a zone that optimizes fat burning. The Zone Diet suggests that the body is genetically inclined to work more efficiently if you consume a ratio of 40 percent carbs, 30 percent protein and 30 percent fat.
Concerns
The Zone Diet implies that carbohydrates cause obesity and that protein -- not calories -- hold the key to weight loss. In "The Zone Diet Phenomenon: A Closer Look at the Science Behind the Claims," Dr. Samuel N. Cheuvront cites a lack of research and evidence to back up Sears's claims about the connection between an "ideal" insulin zone and weight loss. People do, however, lose weight on the Zone Diet, which restricts calories, even though calorie intake is not specifically prescribed.
Statistics
Dr. Michael L. Dansinger, et. al., conducted a randomized trial that evaluated the success rates of 160 participants who were assigned one of four diets, including the Zone, Atkins, Ornish and Weight Watchers diets. Weight-loss results were similar after one year, with total pounds lost ranging from 4.6 lbs. on the Atkins diet to 7.3 lbs. on the Ornish plan. Sixty-five percent of the 40 Zone dieters completed the one-year program. Those who continued with their assigned eating plans for the duration of the study experienced the most weight loss, as well as reduced cardiac risk factors.
References
- Dr. Sears Zone Diet: The Zone 1-2-3 Program
- "Journal of the American College of Nutrition"; The Zone Diet Phenomenon: A Closer Look at the Science Behind the Claims; Samuel N. Cheuvront, Ph.D., R.D.; Feb. 2003
- "Journal of the American Medical Association"; Comparison of the Atkins, Ornish, Weight Watchers and Zone Diets for Weight Loss and Heart Disease Risk Reduction; Michael L. Dasinger, M.D., et. al.; 2005
- MayoClinic.com; Weight Loss: Choosing a Diet That's Right For You; June 2010
- MayoClinic.com; Low-Carb Diet; May 2010
- Harvard School of Public Health: The Best Diet Is the One You'll Follow
Member Comments