Quercetin-rich OPE supplementation significantly reduced the weight and percentage of body fat as measured by DXA (P = 0.02). These effects were not shown in the control group. Levels of blood glucose (P = 0.04) and leptin (P = 0.001 for placebo, P = 0.002 for OPE) decreased in both groups. Significant increases in REE and RQ were observed in both groups (P = 0.003 for placebo, P = 0.006 for OPE) and in the OPE group alone (P = 0.02), respectively.