Obesity and its related complications have become increasingly serious social problems that threaten people's lives. Lactic acid bacteria (LAB) have shown an effective influence on preventing obesity in animal experiments and human clinical trials, but its exact mechanism remains unclear. In this review, LAB and several of its metabolites are taken as the point of penetration. It is aimed to summarize the relationship between obesity and gut microbiota, the efficacy of LAB, and its potential mechanisms of preventing obesity and lipid metabolism. LAB intervention can regulate gut microbiota and improve intestinal permeability which is damaged by a high-fat diet or lipopolysaccharide. Besides this, some metabolites produced by LAB can be involved in regulating host lipid metabolism-related pathways. Short-chain fatty acids, linoleic acid, and gammaaminobutyric acid, taken as representatives here, can participate in the regulation through AMP-activated protein kinase or peroxisome proliferator-activated receptor pathway and bowel-brain axis. Therefore, the ingestion of LAB may become a potential adjunctive treatment for obesity in future.