Orlistat (Xenical by Roche) is a drug designed to treat obesity. Its primary function is preventing the absorption of fats from the human diet, thereby reducing caloric intake. It is intended for use in conjunction with a physician-supervised reduced-calorie diet.
The amount of weight loss achieved with orlistat varies. In one-year clinical trials, between 35.5% and 54.8% of subjects achieved a 5% or greater decrease in body mass, although not all of this mass was necessarily fat. Between 16.4% and 24.8% achieved at least a 10% decrease in body mass. After orlistat was stopped, a significant number of subjects regained weight—up to 35% of the weight they had lost Despite this relatively small body mass effect, there was a 37% reduction in the incidence of type 2 diabetes, a significant difference. This study (XENDOS) proved that the side effect profile of orlistat remained the same up to 4 years. Respondents who lost 5% of their initial body weight in the first three months plus 2.5 gm in the first 4 weeks prior to the study, lost 16.4% of their weight at the end of one year.