Cindy Moore, MS, RD Responds:

Cindy Moore, MS, RD, director of nutrition therapy at the Cleveland Clinic Foundation, responds: Almost any fad diet will help you lose weight in the short-term, and the grapefruit diet is no exception. Fad diets work by restricting calories and prohibiting certain foods while encouraging others. With the grapefruit diet, you eat large amounts of grapefruit and drink grapefruit juice on the (unproven) theory that the fruit contains a fat-burning enzyme that speeds weight loss. But the problem with fad diets like the grapefruit diet is that weight loss is difficult to maintain over the long haul. And by limiting the foods you eat, you may lose out on vital nutrients. Also, grapefruit and certain other foods can interfere with the effectiveness and safety of some medications, so check with your doctor before trying this or any other fad diet. To lose weight safely and keep it off, get help from a registered dietitian who can help you develop a plan tailored to your lifestyle. It should allow you to enjoy the foods you love—just less often and in smaller portions.