Chitosan is a primary ingredient in many of the dietary weight loss supplements sold today. Manufacturers claim that this compound can bind to or “trap” dietary fat, preventing fat absorption and causing fat excretion. However, a study published in the January 2005 issue of the Journal of the American Dietetic Association says products that contain chitosan fail to meet these claims.

Researchers who tested the fat-trapping capacity of chitosan found that the fat trapped was clinically insignificant. “For men, it would take more than 7 months to lose 1 pound of body fat,” the researchers concluded. “For women, no fat was trapped. This study reinforces the importance of testing dietary supplements in people in order to substantiate claims.”