June 19 , 2007
Eric Steele, MD
The first-ever fat blocker diet drug approved by the federal government’s Food and Drug Administration (FDA) will soon be available over the counter to the millions of Americans desperate to lose weight. Named Alli (as in your “ally” in weight control), the drug helps reduce your body’s absorption of fat from the food you eat by about 25%. (It’s generic name is orlistat). Given is limited effectiveness and unpleasant side effects, however, weight watchers might want to look for other friends.
While other diet pills sold in stores and over the Internet claim to be fat blockers, Alli and its prescription version Xenical are the only drugs that have ever been truly proven to work. But “work” is a relative term – even with its FDA approval, Alli does not help much in our battles of the bulge. In studies done by the drug’s manufacturer GlaxoSmithKline (GSK), dieters using the stronger Xenical version of orlistat for a year only lost five pounds on average more than those patients using no medication to help them lose weight. When those patients stopped their Xenical they regained half the weight they lost. The overall benefit of Xenical over just dieting after stopping the medication was about three pounds in a year, for a cost of about $1200.
By comparison, if your weight was stable and you then stopped drinking one can of regular soda per day for a year you would lose about 15 pounds.
Side effects are potentially an unpleasant problem for Alli users, since the combination of Alli and a meal with a lot of fat can cause cramps, diarrhea, and incontinence of loose stool. While it works by blocking fat absorption, users would do well to keep their meal fat content relatively low to reduce risk of these side effects. An Alli starter kit includes a diet book with a lot of low fat recipes, and tips on how to reduce side effect risk. Another option is not to take a pill on a day when you are eating a high fat meal. Another potential side effect problem is inadequate vitamin absorption from your food, since some vitamins must be absorbed with fat from your intestine. GSK recommends that Alli and Xenical users take a multivitamin every day.
According to a Yahoo web site survey about the cost of Alli, a bottle of 120 pills costs about $70, or about 60 cents per pill.
These side effects, and the limited effectiveness of Alli’s big brother Xenical for weight loss, are why American physicians have generally been cool to prescribing Xenical for overweight patients.