Fad Diets Versus Dietary Guidelines (continued)
Reprinted with permission of the American Institute for Cancer Research.

Common Denominators

1. All four of the plans reviewed are essentially low calorie diets. None are advertised as such, however. In fact, each encourages the dieter to eat as much as he or she wants of a particular food. Nevertheless, these diets prescribe a daily caloric intake that is well below average requirements.
   
2. By omitting certain foods, and sometimes even entire food groups, these diets are deficient in such major nutrients as dietary fiber and carbohydrates, as well as in selected vitamins, minerals, and protective phytochemicals. Dr. Atkins, for one, recommends supplementing the diet with nutritional supplements ­ and helpfully offers his own line of products.
   
3. The diets are also out of balance, prescribing a daily dietary intake that is high in protein and fat, low in carbohydrates. These proportions are a far cry from those recommended by AICR and other major health organizations like the American Heart Association and the American Dietetic Association, as well as the Surgeon General and the United States Department of Agriculture.
   
4. On a practical level, such high-protein, high-fat, low-carbohydrate diets tend to promote the loss of water weight. However much this diuretic effect may engender a false sense of accomplishment in the dieter, this weight can and does return quickly.
   
5. If such an imbalanced diet is maintained, the body soon reverts to a fasting state called ketosis, in which the body begins to metabolize muscle tissue instead of fat. Authors of these diets actually advocate "taking advantage" of ketosis to hasten weight loss. In fact, this state is one of the body's last-ditch emergency responses; deliberately inducing ketosis can lead to muscle breakdown, nausea, dehydration, headaches, light-headedness, irritability, bad breath, and kidney problems. In pregnancy, ketosis may cause fetal abnormality or death. It can be fatal in individuals with diabetes.
   
6. Over an extended period of time, all four diets can give rise to other health risks, as well. By restricting carbohydrates, all four diets inevitably lead to a lack of fiber, which can cause constipation and other gastrointestinal difficulties. In addition, the high amounts of cholesterol and saturated fat they prescribe increase the risk of heart disease and, possibly, some cancers. There is recent evidence that a diet featuring excessive protein may leach calcium from the bones.
   
7. Over and above these health risks, however, two of the diets discussed below promote baseless ideas about "food combinations." The elaborate case they make for eating specific foods in a specific order and at specific times has no nutritional basis, and amounts to a kind of magical thinking. Click here to read more about the Glycemic Index, a controversial nutritional concept that many authors of fad diets point to as proof of their theories.

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