Quick weight loss: sorting fad from fact.

This article reviews popular diets for their ability to produce effective weight loss. Most of the "evidence" for fad diets is based on anecdotal findings, theories and testimonials of short term results. The most prominent elements of fad diets are those of ritual and sacrifice. These diets offer quick and painless weight loss while allowing consumption of favourite or tasty foods, but place severe restrictions on certain other foods or food categories. Fad diets often work in the short term because they are low-kilojoule diets in disguise; that is, energy intake as a result of the diet is lower than the person's requirements. Successful long term weight loss depends on the consumption over a long period of time of less energy than is expended. The ideal approach is to increase physical activity while modifying eating behaviour to achieve a nutritionally balanced intake.