Is a detox diet safe and effective?

Elizabeth Somer, M.A., R.D., author of Nutrition for Women (Owl Books, 2003) responds: There's little scientific evidence that the body needs cleansing from detox diets, since it already has systems for breaking down and ridding itself of most harmful things, says C. Wayne Callaway, M.D., an endocrinologist in Washington, D.C.

Nutrition facts about what happens during a detox diet:

1) Ironically, fasting generates toxins. As protein in your muscles and organs is broken down for energy around day two, toxic nitrogen substances such as uric acid are formed; these can tax the kidneys and increase risk for gout.

2) Detox diets also deplete glucose, the No. 1 fuel for your brain. Even a juice fast doesn't supply enough glucose to meet these needs, so the body first turns to stored glucose, called glycogen, in the liver.

3) By the middle of the first fasting day, that resource is exhausted, leaving you lightheaded, hungry, tired, and unable to concentrate. By day two or three, you lose your appetite and even feel slightly euphoric not a result of toxins being released from tissues, but because of a rise in fat fragments, called ketones.

4) In essence, your body is literally consuming itself as it strives to provide energy for the brain and tissues, while metabolism has slowed in an attempt to conserve energy.

5) The weight you lose in the first two to three days of a fast is water and muscle, not fat, says Callaway, who adds that pounds quickly return.