The journal of the Austrian Family Physician had a nice review on the science behind weight loss diets. From a European standpoint, our obsession with these diets seems to be rather curious.
The comment was made that trials have only appeared over the past 3 to 4 years evaluating our major fad diets. All diets seem to work for about 12 months but seem to cease working at the end of the 12 months. No side effects were noted and no safety issues were raised.
The adherence to the diets is difficult. Weight loss is always moderate. It seems that neither the standard recommended restriction of calories nor the popular new weight loss diets are effective.