TYPES OF DIETS
Low-fat
Low-fat diets involve the reduction of the percentage of fat in one's diet. Calorie consumption is reduced but not purposely so. Diets of this type include NCEP Step I and II. A
meta-analysis of 16 trials of 2 - 12 months' duration found that low-fat diets resulted in weight loss of 3.2 kg (7.1 lb) over eating as normal.
Low-carbohydrate diets.
Low carbohydrate diets such as Atkins and Protein Power are relatively high in fat and protein. They are very popular in the press but are not recommended by the American Heart Association.
A review of 107 studies did not find that low-carbohydrate diets cause weight loss, except when calorie intake was restricted. No adverse effects from low carbohydrate diets were detected. Low
carbohydrate diets do not support exercise very well, due to the fact that carbohydrates are the main source of energy during anaerobic exercise, such as sprinting or resistance training, and supply 30% or more during aerobic exercise.
Low-calorie diets
Low-calorie diets usually produce an energy deficit of 500 - 1,000 calories per day, which can result in a 0.5 kilogram (1.1 lb) weight loss per week. They include the DASH diet and
Weight Watchers among others. The National Institutes of Health reviewed 34 randomized controlled trials to determine the effectiveness of low-calorie diets. They found that these diets lowered total body mass by 8% over 3 - 12 months.
Very low-calorie diets
Very low calorie diets provide 200 - 800 kcal/day, maintaining protein intake but limiting calories from both fat and carbohydrates. They subject the body to starvation and produce an average weekly weight loss of 1.5 - 2.5 kilograms (3
- 5.5 lb). These diets are not recommended for general use as they are associated with adverse side effects such as loss of lean muscle mass, increased risks of gout, and electrolyte imbalances.
