They're trendy, they're sexy, they're geographically fabulous (South Beach! Los Angeles!), and they're selling like hotcakes drenched in maple syrup. But do they deliver what they promise? O's medical experts weigh in. Lauren Gravitz reports.

To the dismay of nutritionists—and the delight of diet book publishers—when the majority of Americans want to drop pounds, they think less about long-term lifestyle changes and more about quick fixes. In fact, between 2002 and 2003, diet titles more than doubled their share of overall book sales. To see if any are worth buying, we asked LLuminari, O's team of doctors and nutritionists, to investigate. Each diet was put through a rigorous analysis to determine how many calories it actually gives you in a day (most don't say), what percentage is fat, and whether it has nutritional deficiencies. One point all the experts stressed before starting is that even the best-rated diet won't work unless it's paired with an exercise regimen.

The Books
Browse the latest!

• The South Beach Diet
• The L.A. Shape Diet
• The New Glucose Revolution
• The Maker's Diet
• Eat Right for Your Type
• The Perfect Fit Diet

The Panel  
Robert Lash, MD, an endocrinologist and clinical associate professor of medicine at the University of Michigan Medical School.

Lynne Perry-Bottinger, MD, a cardiologist and assistant professor of clinical medicine at Columbia University College of Physicians and Surgeons.

Miriam Nelson, PhD, director of the John Hancock Center for Physical Activity and Nutrition at Tufts University's Friedman School of Nutrition Science and Policy.

Christina Economos, PhD, assistant professor of nutrition at Tufts University's Friedman School of Nutrition Science and Policy.