Obesity is a growing health problem that many countries face, mostly due to the consumption of a Westernized diet. In this present study we observed the effects of a soybean extract fermented by Bacillus subtilis MORI (BTD-1) containing 1-deoxynojirimycin against high fat diet-induced obesity. The results obtained from this study indicated that BTD-1 reduced body weight, regulated hepatic lipid content and adipose tissue, and also affected liver antioxidant enzymes and glucose metabolism. These results suggest that administration of BTD-1 affects obesity by inhibiting hyperglycemia and free radical-mediated stress; it also reduces lipid accumulation. Therefore, BTD-1 may be potentially useful for the prevention of obesity and its related secondary complications.