Exercise effectively prevents the development of obesity and obesity-related diseases such as type 2 diabetes. Capsinoids (CSNs) are capsaicin analogs found in a nonpungent pepper that increase whole body energy expenditure. Although both exercise and CSNs have antiobesity functions, the effectiveness of exercise with CSN supplementation has not yet been investigated. Here, we examined whether the beneficial effects of exercise could be further enhanced by CSN supplementation in mice. Mice were randomly assigned to four groups: 1) high-fat diet (HFD, Control), 2) HFD containing 0.3% CSNs, 3) HFD with voluntary running wheel exercise (Exercise), and 4) HFD containing 0.3% CSNs with voluntary running wheel exercise (Exercise ϩ CSN). After 8 wk of ingestion, blood and tissues were collected and analyzed. Although CSNs significantly suppressed body weight gain under the HFD, CSN supplementation with exercise additively decreased body weight gain and fat accumulation and increased whole body energy expenditure compared with exercise alone. Exercise together with CSN supplementation robustly improved metabolic profiles, including the plasma cholesterol level. Furthermore, this combination significantly prevented diet-induced liver steatosis and decreased the size of adipocyte cells in white adipose tissue. Exercise and CSNs significantly increased cAMP levels and PKA activity in brown adipose tissue (BAT), indicating an increase of lipolysis. Moreover, they significantly activated both the oxidative phosphorylation gene program and fatty acid oxidation in skeletal muscle. These results indicate that CSNs efficiently promote the antiobesity effect of exercise, in part by increasing energy expenditure via the activation of fat oxidation in skeletal muscle and lipolysis in BAT.exercise; capsinoids; obesity; energy expenditure; fat oxidation OBESITY IS RAPIDLY BECOMING a major global health problem (4) and is a major risk factor for several common diseases, including type 2 diabetes, cardiovascular diseases, and cancer (32). Obesity develops when energy intake chronically exceeds total energy expenditure (51). Conventional antiobesity strategies have focused on repressing energy intake by suppressing appetite or inhibiting intestinal fat absorption; however, increasing energy expenditure by activating the metabolic function of skeletal muscle or brown fat could serve as an alternative and effective antiobesity intervention, thereby avoiding the potential adverse effects associated with conventional antiobesity therapies such as depression, oily bowel movements, and steatorrhea.Exercise is one of the most efficient ways to prevent obesity and type 2 diabetes through an increase in energy expenditure (25, 27, 52). However, people in the developed world are becoming less physically active as a result of lifestyle changes and the nature of their work. Moreover, constraints such as lack of time, limited access. and injuries frequently become barriers to exercise (48). For example, a recent epidemiological study estimated that ...