This is adapted from the book, Eat Smart, Play Hard, by RW USA Nutrition Editor Liz Applegate.
Log on to the Internet, flip through a fitness magazine, or cruise the supplement aisles in a health food store, and youre bound to come across a staggering array of supplements that claim to speed your metabolism and shed unwanted fat.
Many of these products contain a Chinese herb called ma huang, also called ephedra, or a synthetic version called ephedrine. Caffeine is a common ingredient as well. These ingredients show promise as weight-loss aids, but they also have been proven to be dangerous and even deadly for some users.
Both ephedrine and caffeine are powerful central nervous system stimulants, which means that they increase heart rate and blood pressure as well as boost your calorie burn. How they do this isnt clear, but research indicates that they introduce an inefficiency to the body so that it wastes heat energy.
A handful of studies show that weight-loss claims are valid when these supplements are combined with a low-calorie diet. When combined with caffeine, ephedra does enhance fat loss, suppress appetite, and stimulate fat burning beyond what would normally happen on a restricted-calorie diet. In one study, people lost 36 pounds during the 6 months that they took a daily caffeine-and-ephedrine supplement; the placebo group lost 29 pounds.
The problem with this is that the dose that produces this effect is 60 milligrams of ephedrine and 600 milligrams of caffeine, which is the amount in 6 cups of coffee. Many people who take ephedrine and caffeine report that both can cause a speeding heart rate, dizziness, sweating, and other symptoms of nervousness. The FDA has been notified of more than 800 adverse side effects, including heart attack, stroke, tremors, and insomnia. A total of 17 deaths have been blamed on the use of ephedrine, either as an ingredient in a supplement or as a supplement itself.
The FDA recommends that consumers avoid all types of ephedra products, including many weight-loss formulas, and it will soon limit supplements to 8 milligrams of ephedrine per serving and a maximum daily dose of 24 milligrams.
My recommendation: Stay away from these products.