The Zone diet

Originally Published: May 24, 1996 - Last Updated / Reviewed On: May 15, 2009
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Dear Alice,

There is a diet going around called the "Zone Diet." This diet seems to make a lot of sense. I would greatly appreciate your opinion on it.

Sincerely,
Zone Me In

Dear Zone Me In,

Obesity has become an increasingly, um, large issue in the U.S., and theories abound to explain why. Barry Sears, Ph.D. creator of the Zone Diet, believes that the culprit of such wide-spread overweight is insulin resistance, which people develop as a result of eating too many refined carbohydrates and sugary foods. His solution? In addition to exercise, he recommends cutting out much of the sugar and carbs, and eating a lower carb, higher protein, and moderate fat diet in the ratio of 40 percent carbs, 30 percent protein, 30 percent fat.

Sears, a biochemist, has found that a diet high in carbohydrates causes an over-production of insulin, a hormone which helps the body use and store glucose. Too much insulin can lead to weight gain, which is the main focus here, but it can also create an imbalance in eicosanoids, a hormone-like substance that regulates inflammation. An imbalance in eicosanoids has been linked heart disease, cancer, and arthritis. Sears believes that eating a lower carb, higher protein, and moderate fat diet will balance these hormones within the preferred "zone," for most efficient insulin production, weight loss, and hormonal balance. The plan encourages people to eat often throughout the day — at least every five hours — which may help some to keep their metabolism stable, thereby burning calories more efficiently than less-frequent eating which allows blood sugar levels to fall.

The Zone pays special attention to the glycemic index of foods, which is a way to measure how quickly a food becomes sugar in the blood. The more quickly a food breaks down, the quicker it turns to sugar and requires an insulin surge. Low glycemic foods, such as cherries, grapefruit, nuts, and lentils, don't cause blood glucose levels to increase quickly, and therefore require lower levels of insulin than higher glycemic foods, which include white potatoes, corn flakes, and dates.

The diet focuses on strictly limiting high-glycemic foods, such as sweets, chips, and starches, and replaces them with more nutrient-rich and lower-glycemic choices like vegetables, some fruits, grains, lean meats and fish, and monounsaturated and omega-3 fats. Low-glycemic foods tend to be low in calories, so a significant reason people lose weight while on the Zone is because it is essentially a low-calorie diet.

Another reason some people tend to quickly lose weight on the Zone Diet is because of water loss. Because The Zone encourages people to eat significantly more protein than they were eating before, the body uses its own water (and we are 70 percent water) to digest this protein. Followers notice that they seem to be shrinking, and they are, but often because of dehydration. It is important to drink plenty of water on this diet to prevent dehydration, and to make sure the weight coming off is not just water.

Of course no two people have the same eating patterns, hormonal profiles, and genetics, so the same diet can't work in the same way for everyone. Weight control is much more complex than simply following a prescribed eating plan or a meticulous balance of nutrients. The satisfaction a person derives from his or her food is key in forming a healthful eating plan. For some, slightly higher carbohydrate intake is more satisfying; for others, slightly higher protein works better — the important part is eating a variety of whole unprocessed foods, keeping active with regular exercise, and making these changes permanent and sustainable, and not to mention, enjoyable.

The best approach to nutrition is one that allows you to enjoy that pleasure of eating a variety of foods while feeling healthy, fed, and fit.

Alice