Metabolic role of lactobacilli in weight modification in humans and animals

Obesity represents a worldwide public health crisis. Trials suggested that intestinal microbiota may contribute to the development of obesity and highlighted the involvement of bacteria, including Lactobacillus spp., in changes to the host metabolism. Several experiments have shown significant effects of Lactobacillus probiotics on weight modification. Lactobacillus spp. are involved in the digestion of complex carbohydrates not digested by the host in the colon and also participate in the degradation of lipids and simple sugars in the duodenum and jejunum. Moreover, Lactobacillus species survive throughout the gastrointestinal tract, as they are able to survive in the presence of bile and low pH, and produce an antimicrobial agent, allowing them to reduce the number of bacteria in the gut. Hence, Lactobacillus spp. can have a significant impact on microbiota and, consequently, on weight change. Here, we review current studies of Lactobacillus spp. involved in weight change and discuss the different mechanisms of action by which Lactobacillus spp. acts on host digestion and appears to influence weight. •The metabolic profile of Lactobacillus is a masterpiece in the understanding of the physiopathology of obesity.•Lactobacillus spp. are implicated in the digestion of carbohydrates and lipids, they influence fat storage and body weight.•Lactobacillus strains can colonize the digestive tract and proliferate at the expense of other bacteria.•Bacteriocin can contribute to the change in gut composition of obese microbiota and may be directly responsible for it.•Several of the findings about Lactobacilli are strain-specific, highlighting the wide diversity of the genus.