The Zone diet is an unproven dietary regime, which has been popularized by Dr. Barry Sears through sales of his 1995 book, The Zone. Despite claims made in the book, there is little available research to support its overall benefit.
The Zone diet is a calorie-restricted diet that provides adequate protein, moderate levels of carbohydrates, essential fats and micronutrients spread through three meals and two snacks that approximately maintain the protein-to-carbohydrate ratio throughout the day.
Proponents believe that the Zone diet promotes optimal metabolic efficiency in the body by balancing the hormones insulin and glucagon. Insulin is responsible for converting, in the blood, incoming nutrients into cells. Glucagon regulates glucose in the liver. Overall, the Zone's food plan consists of a dietary intake of 40% carbohydrates, 30% protein and 30% fat.
Under this diet, recommended foods include fruits and vegetables (fresh or frozen), oatmeal (whole grain), protein powder (e.g. soybean isolate), chicken, turkey, lean beef, fish, low-fat cottage cheese, soy food, nuts (e.g. almonds, cashews, macademia, pistachios), extra virgin olive oil, natural sweeteners, such as fructose or stevia.
Recent research seems to indicate that a low total caloric intake is associated with longer life expectancy. Based on animal studies, animals eating calorie-restricted diets may live 1.5 to 2 times as long as animals eating high-calorie diets. Theoretically, similar effects may occur in humans. The caloric restriction recommended by the Zone diet is below that of the average American and may be of benefit in weight loss and if maintained over decades in increasing life expectancy. On the other hand, athletes in training will likely suffer from decreased performance if restricted to the low calorie diet recommended by the Zone.
Despite proposed benefits, currently there are no high quality clinical trials available about the Zone diet or similar diets consisting of the recommended 40% carbohydrates, 30% fat, and 30% protein. The Zone diet is quite complex in terms of caloric restriction, ratio of carbohydrates/protein//fat, spacing of meals, preferential intake of certain fats, and avoidance or inclusion of a few specific foods.
Following the wheat free diet involves eliminating all wheat products from the diet. This requires careful attention when reading food labels. Some manufacturers require provide information on their products indicating if contamination with wheat is possible, but this is not always the case.
Individuals are advised to read labels and be able to recognize wheat constituents as ingredients. Alternative food items exist for those wishing to exclude wheat from their diets and are available at most specialty and natural food stores.
Currently, the only effective method of managing a true wheat allergy is avoidance of any wheat-containing products. Some evidence suggests that certain antihistamine medications such as fexofenadine (Allergra) may prevent allergic symptoms when taken before ingestion of wheat in patients with a mild allergy.
The information in this monograph is intended for informational purposes only, and is meant to help users better understand health concerns. Information is based on review of scientific research data, historical practice patterns, and clinical experience. This information should not be interpreted as specific medical advice. Users should consult with a qualified healthcare provider for specific questions regarding therapies, diagnosis and/or health conditions, prior to making therapeutic decisions.