The current obesity pandemic imposes a major global disease burden. However, sustained weight loss of between 5 and 10% in the obese confers marked health benefits. Currently available pharmacotherapies, orlistat and sibutramine, can induce weight loss of between 5 and 10% over 2 years or more. However, in these trials, drug induced weight loss tends to be only 2-4 kg greater than that produced by placebo control. Despite this, in the XENDOS trial, the modest placebo-subtract weight loss produced by orlistat (2.8 kg) reduced the incidence of diabetes by over a third. Recent data on the potential anti-obesity drug rimonabant are also reviewed.