How the Zone Diet Works

The Zone diet by Dr Barry Sears is a very carefully controlled eating plan based upon the principle of 40% carbohydrate, 30% fat and 30% protein. No matter how many calories you eat in a day, at a meal or snack, the distribution of food groups should always be 40-30-30. Very much like his friends Drs Mary Dan and Michael Eades, his diet is based upon controlling the amount of insulin in your system at any one time and he warns against not eating enough protein in a day. Unlike the Eades', however, his diet allows for more daily carbohydrate content.

For Dr Sears, The Zone refers to the very narrow margin of safety within which the hormone insulin needs to be maintained. When insulin goes out of control, the body suffers. His books extensively cover the chemical processes involved in food consumption, describing what happens when we eat too much carbohydrate and what happens when we eat too little.

The 40-30-30 concept is an easy one to grasp but difficult to put into practice. Dr Sears' books have many recipes and food plans to help the dieter implement his system.

One of the practical aides to implementing his program is what he calls "food blocks." Because it's hard to balance a diet perfectly at 40-30-30, he devised calorie, ounce and gram counts into "blocks" for each food group. A protein "block" consists of approximately seven grams of protein or between one to one and a half ounces of a protein depending upon the fat content. (One ounce for fatty meats like beef, and one and one half ounces for lean meats like fowl.) A carbohydrate block consists of nine grams per block. He does suggest foods within each category that he believes are the "healthiest." Each book provides lists of foods and their amounts that add up to "one block." The task of the dieter is to select equal numbers of blocks of each food group per meal or snack. For example, a snack would consist of one block each of protein, fat and carbohydrate. The fats are the hardest to maintain within the 30% range as the fats in protein and carbohydrates need to be calculated into the equation as well as the "pure" fats.

Other useful aides to dieting include a food pyramid (p. 49, Mastering the Zone) with water at the base of the pyramid, fruits and vegetables at the second level, low-fat proteins at the third level, monounsaturated fats at the fourth level and breads, grains, starches and pasta at the tip of the pyramid (he suggests they be treated like condiments). This gives the dieter a good idea of just which foods should be eaten and which should be avoided.

Sears is more concerned about fat loss than he is about total weight loss. In "Enter the Zone" he provides methods of calculating body fat for both men and women using similar constants to those provided by the Eades in "Protein Power." Like the Eades, he also gives calculations for minimum daily protein requirements. An interesting little aside, is the recommendation to start any meal or snack by eating the protein first, or at least start with the protein, in order to slow the body's response to it's reaction to ingested carbohydrates. A good suggestion no matter what diet you follow.

Dr Sears has had good success implementing The Zone diet with athletes but was not as successful with overweight women over forty who tried to implement his diet by reading his books alone. These women abandoned The Zone diet before the women on the Atkins diet stopped dieting. The difficulties in trying to maintain a 40-30-30 balance may have proved too much.

Whether or not you are interested in, or want to follow, the prescribed Zone diet, the Zone books themselves are well worth reading. They provide a wealth of information about human physiology and the effects of diet upon the system. "The Omega Zone" for example explains why we should be supplementing our diet with Omega 3's.

References

Barry Sears, PhD, (with Bill Lawren) Enter the Zone and Mastering the Zone

Michael and Mary Dan Eades, Protein Power and Protein Power Life Plan

Comparison of the Atkins, Zone, Ornish and LEARN Diets for change in weight and related risk factors among overweight premenopausal women: the A - Z Weight Loss Study: A Randomized Trial. Journal of the American Medical Association. March 7, 2007; Vol. 297: 969-77.