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Activity calculator


Also listed as: Diet, Zone
Related terms
Author information
Recommended activity levels

Related Terms
  • Adequate protein diet, Barry Sears, carbohydrate, diet, fat, low carbohydrate diet, protein.

  • 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.

Theory / Evidence
  • 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.


Author information
  • This information has been edited and peer-reviewed by contributors to the Natural Standard Research Collaboration (

  1. Cheuvront SN. The zone diet and athletic performance. Sports Med. 1999;27(4):213-228.
  2. Natural Standard: The Authority on Integrative Medicine.
  3. Sears B. The Zone Diet and athletic performance. Sports Med. 2000;29(4):289-294.

Recommended activity levels
  • Health related organizations make slightly different specific recommendations as to the number of times an individual should exercise per week. However, the overall consensus is at least 30 minutes of exercise for 3 days or more per week. Maintaining an exercise schedule is very important in achieving physical fitness.
  • American College of Sports Medicine: For cardio-respiratory fitness and body composition: 20 to 60 minutes of continuous or intermittent (bouts of at least 10 minutes) aerobic activity at 55 to 90% maximum heart rate, or at 40 to 85% maximum oxygen uptake, 3 to 5 days per week. For muscular strength and endurance, body composition and flexibility: One set of 8 to 10 exercises, with 8 to 12 repetitions of each exercise, 2 to 3 days per week.
  • American Heart Association: 30 to 60 minutes of exercise at 50 to 80% aerobic capacity, at least 3 to 4 days per week.
  • International Agency for Research on Cancer: To maintain healthy body weight: 60 minutes moderate activity on all or most days of the week. For cancer prevention: Substitute moderate for vigorous activity several times per week.
  • International Association for the Study of Obesity: To prevent weight regain in formerly obese individuals: 60 to 90 minutes of moderate activity daily, or shorter periods of vigorous activity. To prevent transition to overweight or obesity: 45 to 60 minutes of moderate activity daily, or 1.7 PAL. For children, more activity time is recommended.
  • CDC: 30 minutes of moderate activity on all or most days of the week.
  • World Cancer Research Fund/American Institute for Cancer Research: 30 minutes of vigorous or 60 minutes of moderate activity daily, plus additional 30 to 60 minutes of vigorous activity once a week.
  • World Health Organization: 30 minutes of moderate activity every day.

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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.

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