BY GLEN PETERSON

The grapefruit diet has been around for almost 100 years, but does it really work? Not in the long run. Sure, you’ll lose fat, but it’s mostly due to water loss and you’ll gain it back quickly as soon as you go off your diet. Your body may even rebound, leading to greater fat gains than what you’ve lost. Grapefruit is, however, great in moderation. Rich in vitamin C, potassium and dietary fiber, it’s an excellent addition to most healthy diets – unless you’re taking certain medications.

"The chemicals in grapefruit interfere with the enzymes that metabolize drugs in the digestive system," says Katherine Zeratsky, a dietitian with the Mayo Clinic. As little as eight ounces of grapefruit juice can interact with calcium channel blockers, cholesterol-lowering drugs and other medications for up to 72 hours, often potentiating their effects and leading to serious side effects. If you’re taking any medications, check with your doctor to make sure that it’s OK to eat grapefruit. Medical ramifications aside, while grapefruit provides great health benefits, there is no scientific validation that it represents a magic bullet for the overweight.

For many more valuable fat loss tips, pick up the latest January/February issue of Maximum Fitness -- on newsstands December 15, 2009.