Xenical is a prescription drug designed to help significantly overweight people lose weight. It is a version of Alli, the only diet pill that is approved by the FDA.

According to the manufacturers, Xenical is different from other diet pills because instead of suppressing your appetite or speeding up your metabolism, it blocks about one-third of the fat you eat from being digested. The undigested fat cannot be broken down and is eliminated through your bowel movements.

However, Xenical is not a magic pill.

"Xenical is a weight-loss drug that can have significant side effects and in blocking the absorption of fat to encourage weight loss, may also block the absorption of important vitamins, minerals and healthful fats required by the body," says Marissa Lippert, RD, of Nutrition Counseling & Communications. "Weight-loss drugs are temporary fixes, rather than lasting solutions. It's important to remember that in order to healthfully lose weight and sustain it, fresh food in the appropriate portion sizes should be the primary focus."

The American Heart Association agrees and recommends reduced-calorie diets that typically allow for no more than 30 percent of your daily caloric intake to come from fat.

Possible side effects include uncontrollable bowel movements, gas and oily discharge.

If you think Xenical may be right for you, speak to your doctor.

At That's Fit, we've got great food ideas, exercise plans and more to help you lose weight.