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 (sd 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.