Obesity Weight Loss Drugs Fat Blockers

Fat blockers aim to prevent the absorption of fat during digestion, excreting it in stool instead. Fat blocker pills come in two varieties: natural fat blockers and orlistat, the only non-prescription fat blocker approved by the U.S. Food and Drug Administration. Many natural fat blockers are also available as dietary supplements.

Natural Fat Blockers and Chitosan

The primary ingredient in most natural fat blockers is chitosan, a substance derived from shellfish. According to natural fat blockers’ manufacturers, chitosan has the ability to bind to fats in the digestive system. Exactly how chitosan does this isn’t clear, but some manufacturers claim that chitosan can absorb fat up to 10 times its own weight.

More exuberant (or perhaps dishonest) marketers claim that fat blocker users can eat as much fat as they please. Some companies even report that this treatment for obesity prevents heart disease and cancer (claims that the FDA took issue with).

Fat Blocker Pills: Clinical Studies

Few clinical studies have tested chitosan’s fat blocking capabilities as a treatment for obesity. A small-scale study published in the journal Obesity Research r(2003) eported that chitosan fat blockers increased fats in fecal matter by one gram, an amount that would have no impact on weight loss. Excessive use of fat blocker pills can cause cramping, diarrhea and excessive gas.

Still, natural fat blockers pills remain very popular. If you’re interested in trying fat blockers, discuss it first with your doctor. While shopping for fat blocker pills, be aware that many “best fat blockers” review sites online are generally more interested in selling their products, rather than providing an unbiased comparison.

Orlistat as a Treatment for Obesity

Orlistat is a fat blocker available in both prescription and over-the-counter strengths. Orlistat reduces fat absorption to promote weight loss. People taking orlistat should eat a low-fat diet, since too much fat in the diet may aggravate orlistat’s side effects. Most orlistat side effects occur because unabsorbed fat passes out of the body through bowel movements.

Common side effects of this treatment for obesity include gas, inability to control bowel movements, oily discharge and oily stools.

While taking orlistat, reduced fat intake may alleviate these side effects. Your doctor may also recommend taking a multivitamin, since fat blocker pills prevent the absorption of certain nutrients along with the fat itself.


Barrett, S. (n.d.). Is chitosan a “fat magnet”? Retrieved April 30, 2010, from http://www.quackwatch.org/04ConsumerEducation/QA/chitosan.html.

Gades, M. D.