How It Works

The Zone's eating plan is a combination of a small amount of low-fat protein at every meal, fats, and carbohydrates in the form of fiber-rich vegetables and fruits. The plan establishes a ratio for which Sears contends the body is genetically programmed (that 40-30-30 figure). And yes, we'll be thinner to boot.

Sears claims that the diet is based on his 15 years of research in bio nutrition. Although the book is full of success stories, including those of elite athletes, research that validates his specific claims isn't there. That doesn't mean that Sears' theories are wrong; it's just that no scientific evidence has proven that his program works.

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 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. In other words, you must be mindful of what you put on your plate. Sears suggests that we think of food not as "a source of calories but as a control system for hormones."