Obesity is a serious and costly issue to the medical welfare worldwide. Probiotics have been suggested as one of the candidates to resolve the obesity-associated problems, but how they combat obesity is not fully understood. Herein, we investigated the effects of Lactobacillus reuteri 263 (L. reuteri 263) on antiobesity using four groups of Sprague-Dawley rats (n=10/group), namely, C (normal diet with vehicle treatment), HE [high-energy diet (HED) with vehicle treatment], 1X (HED with 2.1×109 CFU/kg/day of L. reuteri 263) and 5X (HED with 1.05×1010 CFU/kg/day of L. reuteri 263), for 8 weeks. L. reuteri 263 improved the phenomenon of obesity, serum levels of proinflammatory factors and antioxidant enzymes. More importantly, L. reuteri 263 increased oxygen consumption in white adipose tissue (WAT). The mRNA expressions of thermogenesis genes uncoupling protein-1, uncoupling protein-3, carnitine palmitoyltransferase-1 and cell death-inducing DFFA-like effector-a were up-regulated in WAT of the 5X group. Moreover, L. reuteri 263 might induce browning of WAT due to the higher mRNA levels of browning-related genes peroxisome proliferator-activated receptor-γ, PR domain containing-16, Pparγ coactivator-1α, bone morphogenetic protein-7 and fibroblast growth factor-21 in the 1X and 5X groups compared to the HE group. Finally, L. reuteri 263 altered the expressions of genes involved in glucose and lipid metabolisms in WAT, including increasing the levels of glucose transporter type 4 and carbohydrate-responsive element-binding protein and decreasing the expression of Acetyl-CoA carboxylase-1. The results suggest that L. reuteri 263 may treat obesity through energy metabolism remodeling of WAT in the high-energy-diet-induced obese rats.