They claim to prevent or treat such diseases as high blood pressure, diabetes, gout, atherosclerosis, and gall stones. The American Medical Association has questioned the safety and effectiveness of high-carbohydrate diets, particularly regarding the diseases they are supposed to prevent. At best, research says, they are no better than other diets aimed at preventing peripheral vascular diseases. At worst, they could lead to reduced resistance to infection and poor healing of wounds because of the lower fat and protein intakes. Dieters are encouraged to eat often and even carry around raw vegetables to eat all day.
Some plans recommend the addition of a fiber product to the diet.
While there seems to be some value in having a high-fiber content in our diet, this is only one factor in a properly balanced diet. Researchers have not found it to be the solution to obesity. An undue emphasis on bran may result in increasing dietary bulk and satiety, but it also has some adverse effects. Diets high in fiber cause increased gastrointestinal motility and other side effects such as gas and diarrhea. Also, they have been reported to decrease absorption of important trace elements.