The Zone Diet was developed by Barry Sears, PhD, and popularized by Dr. Sears’
best-selling book, The Zone: A Dietary Road Map to Lose Weight Permanently: Reset Your
Genetic Code: Prevent Disease: Achieve Maximum Physical Performance: Enhance Mental
The foundation of the Zone Diet is the relationship between the hormone insulin and
substances called eicosanoids. Eicosanoids are hormone-like substances that control many vital
physiological functions, including those of the cardiovascular system, immune system, and
nervous system. Dr. Sears believes that certain eicosanoids are “good” and others
Here’s where insulin enters the picture. When insulin levels are high,
“bad” eicosanoids are produced. Dr. Sears contends that his Zone Diet, which
contains 40% carbohydrate, 30% protein, and 30% fat, is the ideal diet for keeping insulin
levels in check.
Why do people follow this diet?
The Zone Diet is popular among people desiring to lose weight. Even though the diet is low in calories,
it contains enough fat to provide a sense of fullness. In addition, normalizing insulin levels
can eliminate food cravings, making it easier for dieters to not cheat. Many athletes seek to
live in “the Zone” because they believe following the diet leads to improvements
in body composition and enhances athletic
performance. The Zone Diet is also popular among people with non-insulin dependent diabetes, as it is believed to help normalize
blood sugar levels.
What do the advocates say?
Advocates of the Zone Diet contend that living “in the Zone” improves energy
levels, mental clarity, physical endurance, and promotes weight loss. Dr. Sears has worked
with many elite athletes and attributes their success in competition to his diet.
What do the critics say?
Most nutrition professionals favor a high-complex-carbohydrate, low-fat diet for general health and weight loss. They
caution that high-protein, low-carbohydrate diets lack key nutrients for health, including
dietary fiber, vitamin C, folic acid, and several minerals. In addition, the
high intake of meat products necessary to meet
the protein requirements of the Zone Diet may place certain individuals at risk of heart disease due to increased intake of saturated fat and cholesterol. Persons with kidney failure are also
warned to stay away from the diet, as high amounts of protein increase the amount of
nitrogen-containing waste products the kidneys must process for elimination.
Critics of the Zone Diet concede that people who follow the diet carefully often experience
significant weight loss. However, they point
out that the Zone Diet is actually very low in calories, with the average person taking in
only 800—1,200 calories per day, and caution that the strict, and confusing, nature of
the diet makes it difficult to follow. As a result, long-term compliance—and therefore
lasting weight loss—with this diet is unlikely. Moreover, any diet low enough in
calories will result in weight loss, regardless of its proportions of protein, carbohydrate,
Not all sports nutritionists and athletes believe that the Zone Diet is ideal for athletic
training and performance. A significant amount of research in the field of exercise physiology
has shown that fatigue during exercise is primarily caused by depletion of the body’s
stored carbohydrates (called glycogen). Most athletes’ glycogen stores are depleted
within 90 minutes of intense exercise, leaving muscles without any source of energy to fuel
activity. As a result, many experts believe that a sufficient intake of carbohydrates before
and during exercise is crucial for increasing endurance.
Are there any groups or books associated with this diet?
The Zone by Barry Sears, New York: Harper Audio, 1998.
A Week in the Zone by Barry Sears, New York: Regan Books,
Mastering the Zone: The Next Step in Achieving Superhealth and
Permanent Fat Loss by Barry Sears, New York: Regan Books, 1997.
The Top 100 Zone Foods: The Zone Food Science Ranking System
by Barry Sears, New York: Regan Books, 2001.
Zone-Perfect Meals in Minutes: 150 Fast and Simple Healthy
Recipes from the Bestselling Author of the Zone and Mastering the Zone by Barry Sears,
New York: Regan Books, 1997.
Zone Food Blocks: The Quick & Easy, Mix & Match Counter
for Staying in the Zone by Barry Sears, New York: Regan Books, 1998.
The Soy Zone by Barry Sears, New York: Regan Books,
The Anti-Aging Zone by Barry Sears, New York: Regan Books,
The Age-Free Zone by Barry Sears, New York: Regan Books,
The Zone Diet Web site
Sears, Barry PhD. Enter the Zone. New York: Harper Collins,
Stein, Karen. High-protein, low-carbohydrate diets: Do they work?
J Am Dietet Assoc 2000;100:760–1.