Review of Zone Diet

Zone Diet was created by Barry Sears, PhD, a former researcher in biotechnology at the Massachusetts Institute of Technology. The Zone offers more than just weight-loss claims. By retooling your metabolism with a diet that is 30% protein, 30% fat, and 40% carbohydrates, Zone Diet contends that you can expect long-term health benefits, such as a reduced risk of heart disease, high blood pressure, and diabetes. Another much-touted advantage is better athletic performance.

Zone Diet does not recommend that you eat fewer calories than you're currently consuming, just different ones. The diet keeps saturated fats to a minimum, but includes olive, canola, macadamia nuts, and avocados. Certain unfavorable carbohydrates are restricted because they release glucose quickly: grains, breads, pasta, rice, and other similar starches, a deviation from conventional definitions of a good diet. Overall, the diet is higher in protein and fat than traditional diets.

Zone Diet’s list of allowable foods includes some sure-to-please high-fat foods such as ice cream.  The theory being that the fat retards the rate of absorption of carbohydrate into the body. These high-fat foods are available through the diet in very small quantities, but they will help control cravings nonetheless.

Zone Diet establishes a ratio for which Sears contends the body is genetically programmed (30% protein, 30% fat, and 40% carbohydrates). Sears bases his theory on using diet to control the body's production of the hormone insulin. Among insulin's many roles, it helps regulate storage of excess energy as fat. The goal of Zone Diet is to keep a balance between fat-storing insulin and the hormone glucagon, insulin's opposite, whose job it is to release the stored glucose from the liver when it is needed. Maintaining the correct balance between the two is accomplished by watching the size and specific content of your meals.