How Does The Zone Diet Work?

Developed in the 1970s by biochemist Barry Sears, Ph.D., to combat heart disease and fight obesity, the Zone diet also claims to increase your daily energy stores, slow down physical aging and boost mental function. Twenty years after beginning his research, Sears published his first book "Enter the Zone" in 1995, and he followed that with the publication of numerous Zone recipe books. Today, the Zone diet is a large commercial diet that even delivers meals to its members.

Carbohydrate vs. Protein

Sears claims that the Zone diet, through strict control of carbohydrates and proteins, creates a hormonal balance in the body that boosts health and encourages fat loss. Unfortunately, Sears' claims are not backed by hard evidence. U.S. Army researcher and physiologist, Samuel N. Cheuvront, Ph.D., reported in 2004 that the Zone diet's claims were "dubious" and based upon "misinterpreted scientific facts."

Ratios

The Zone diet requires strict adherence to specific food ratios. Every time a Zone dieter eats a meal, it must contain 40 percent carbohydrates, 30 percent protein and 30 percent fat. The commercial end of the Zone diet sells pre-packaged meals with the correct ratio of food types. These ratios are the cornerstone of the Zone diet. Dieters who prepare their own meals must also follow these ratios.

Timing

In addition to strict carb/protein ratios, the Zone diet requires adherents to eat snacks and meals on a specific schedule. Dieters must eat breakfast within one hour of waking in the morning and consume three approved meals and two snacks each day. The dieter must always eat within 5 hours of the last snack or meal and should drink more than 8 cups of water every day. Dieters must also exercise daily and meditate.

Allowed Foods

On the Zone diet, Sears allows foods he considers healthy, as long as the dieter eats them in the correct ratios of 40 percent carbohydrates, 30 percent protein and 30 percent fat. Allowable proteins include lean poultry, fish and seafood, skim or non-fat dairy products and egg whites. Non-starchy carbohydrates include fruits and vegetables, barley, oatmeal and small amounts of other grains. The dieter may use olive oil and canola oil in salads and food preparation to fulfill the fat requirement. In his books, Dr. Sears lists all allowable foods as either carbohydrates, proteins, fats or as a combination of these categories.

Restricted Foods

The Zone diet prohibits red meat and organ meats, and starchy vegetables such as corn, potatoes and carrots. The diet restricts many fruits as well, including bananas, mango, papaya and most fruit juice. Most baked goods are eliminated and so are caffeinated coffee, tea and whole milk. Zone dieters do not drink alcohol or diet sodas.

Considerations

Due to the high level of protein in the Zone diet, it may not be safe for those who with kidney disease. In addition, the "Gale Encyclopedia" warns that pregnant women and nursing mothers may not get enough calories on the Zone diet. Additional problems include an increased risk of developing osteoporosis because on inadequate vitamin D and calcium in the Zone diet, according to the Department of Preventive Medicine at Northwestern University in Chicago. Visit with your doctor before starting any new diet.