The Zone Diet, developed by Dr. Barry Sears, is a dietary program that strives to promote hormone balance, control inflammation and achieve weight loss. The eating plan recommends getting 40 percent of your calories from carbohydrates, 30 percent from protein and 30 percent from fat. This level of carbohydrates is less while the level of protein is more than what is recommended by the National Institutes of Medicine Food and Nutrition Board. Although many patients successfully lose weight on the Zone Diet, it can also lead to problems.
Increased LDL
Cholesterol is a waxy, fat-like substance produced by cells in the body and contributed to by foods you eat. In order to travel in the blood, cholesterol must bind to specialized proteins known as lipoproteins. Low-density lipoprotein, known as LDL or "bad" cholesterol, binds cholesterol and keeps it in the blood. High-density lipoprotein, known as HDL or "good" cholesterol, carries cholesterol to the liver, which breaks it down and removes it from the body.
The Zone Diet emphasizes eating proteins. The best sources of proteins include animal products such as meats and dairy products. Unfortunately, in consuming these animal proteins, you often also consume added fats, including saturated fats. Saturated fat contributes to increasing levels of LDL. As LDL increases, cholesterol can accumulate in the blood vessels, forming plaque. This restricts the flow of blood and can contribute to heart disease.
Decrease in Muscle Mass
The Zone Diet promotes weight loss by restricting your carbohydrate intake as well as your total calorie intake. The diet recommends that each of your three meals contain of no more than 500 calories and that each snack contribute 100 calories or less. That combines to a total of 1,700 calories per day. The reduction in calories along with the restriction in carbohydrates causes the body to obtain more energy by breaking down current muscle cells instead of burning fat, as described by the American Heart Association. Therefore this diet promotes the loss of lean muscle mass instead of the loss of fat.
Weakened Bones
The body uses the proteins from foods to build the thousands of proteins required to support normal body functions. Upon ingesting proteins, enzymes in your digestive system break the proteins down into the individual amino acids that form the proteins. The body then uses the amino acids to build new proteins. During this process, the body releases acids. To neutralize the acids, the body produces and releases buffering substances such as calcium phosphate. To make calcium phosphate, the cells pull calcium from bones. Consuming increased levels of proteins increases the acidity and requires the body to pull additional calcium from the bones, leaving the bones weak and vulnerable to osteoporosis, as described by the U.S. Department of Agriculture.
Ketosis
Ketosis describes a condition in which the body contains elevated levels of ketone bodies. Ketone bodies are produced when the body must break down fats for energy due to a decreased level of glucose. Since carbohydrates are the main source of energy for the body, restricting your carbohydrate intake forces the body to produce glucose from other substances. Although it may sound like a positive to use fat to produce energy, ketosis can become a life-threatening condition leading to liver damage and coma. Dr. Sears and proponents of the Zone Diet maintain that ketosis rarely occurs when following the diet, but the Physician's Committee for Responsible Medicine indicates that patients following any high-protein diet should be aware of the possibility.
References
- National Institute of Medicine: Food and Nutrition Board: Dietary Reference Intakes
- American Heart Association: High-Protein Diets
- Physicians Committee for Responsible Medicine: Atkins Diet Alert
- University of Wisconsin: Ketones in Biology
- American Heart Association: About Cholesterol
- United States Department of Agriculture: Boning Up on Osteoporosis
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