Effect of capsaicin on substrate oxidation and weight maintenance after modest body-weight loss in human subjects

The aim of the present study was to investigate whether capsaicin assists weight maintenance by limiting weight regain after weight loss of 5 to 10%. In this randomized double-blind placebo-controlled study, ninety-one moderately overweight subjects were randomly assigned to an intensive group that underwent all the measurements, and an extensive group that underwent the same measurements except the metabolism measurements. After a 4-week very-low-energy diet (VLED) intervention, a 3-month weight-maintenance period followed. During weight maintenance, subjects were divided into a capsaicin (135 mg capsaicin/d) and a placebo group. Body mass was measured before and after the VLED and after 1, 2 and 3 months of weight maintenance. The mean body-mass loss during the VLED was 6.6 (SD 2.0) kg (7.8 (SD 1.8) % initial body mass), and was not different between the subsequent treatment and placebo group. During weight maintenance, mean % regain during treatment was not significantly different compared with placebo (33.3 (SD 35.7) v. 19.2 (SD 41.8)%, P=0.09). RQ was significantly less increased during weight maintenance in the treatment group compared with placebo (0.04 (so 0.06) v. 0.07 (SD 0.05), P<0.05), indicating a relatively more sustained fat oxidation. Fat oxidation (g/h) after weight maintenance was higher in the capsaicin group compared with placebo (4.2 (SD 1.1) v. 3.5 (SD 0.9), P<0.05). These results indicate that capsaicin treatment caused sustained fat oxidation during weight maintenance compared with placebo. However, capsaicin treatment has no limiting effect on 3-month weight regain after modest weight loss.