Q. A friend of mine lost a lot of weight by doing a detox diet. Are detox diets healthy for you?

A. There are certainly better ways for you to drop a few pounds. Detoxification, or cleansing, diets aim to rid your body of disease-causing "toxins" by limiting the types and amounts of food you can eat. Some plans permit nothing except certain fruits and vegetables (which are often spun into juices), while the popular Master Cleanse fast restricts you to a cayenne pepper-laced elixir for 10 days.

Since the daily calorie count for many detox plans tops out at 700, you will slim down if you follow them, says David Grotto, R.D., founder of Nutrition Housecall, a personal- consulting company in Elmhurst, Illinois. But the weight you'll lose will consist of water and lean muscle tissue rather than body fat. And don't expect to be thinner for long: Because these detox diets put your body into starvation mode, it hangs on to every calorie to conserve energy. The loss of lean muscle mass dampens your calorie-burning furnace as well. So once you revert to your old eating habits, says Grotto, your metabolism will have slowed down, making you even more likely to regain the weight. Vitamin deficiencies are also possible, especially with the plans that limit fruits and veggies.

What's more, the whole concept of detox diets is misleading and it's a better strategy to stick to a balanced healthy diet. "Your liver and other organs naturally remove so-called waste from your body," says Grotto. "Eating whole grains, produce, healthy fats, lowfat dairy, and lean protein keeps these organs and your body's elimination process in top condition. If you cut your calorie intake to 1,500 daily, you'll lose weight, too."