Obesity is defined as excessive accumulation of body fat, caused by an energy imbalance. Approximately 13% of the world's adult population is obese, and in Brazil 19.8% of adults are obese. This disease is a risk factor for the development of other non-communicable chronic diseases (NCDs), such as: type 2 diabetes mellitus (DM2), dyslipidemia, cardiovascular diseases, musculoskeletal disorders and some types of cancer. It is a complex and multifactorial disease, which is why it is considered difficult to control and a cause for global concern. Among the causes of the disease, genetic, environmental and psychological factors can be mentioned, in addition to the interference of the intestinal microbiota, among others.~The interaction of the intestinal microbiota with the host has been studied through metabolomics, in order to understand the influence that the microbiota can exert on the functioning of the host organism. The study of the profile of low molecular weight metabolites of biological fluids such as serum/plasma and urine aims to understand the metabolic changes that occur in individuals with obesity, encompassing the understanding of the mechanisms of the disease.~Studies have shown differences in the metabolic profile of obese individuals compared to eutrophic individuals, with a positive correlation between body mass index (BMI) and increased concentrations of chain amino acids (BCAA) and glutamate. The gut microbiota appears to play a crucial role in host metabolism, being a pathway through which it leads to changes associated with obesity.~In this context, the intestinal microbiota can be modulated by prebiotics, probiotics and symbiotics, promoting changes in its composition, resulting in the regeneration of the intestinal barrier and, with that, ceasing metabolic endotoxemia and low-grade inflammation.~In addition, they have effects on the modulation of the immune system, regulating the production of pro and anti-inflammatory cytokines, reducing IR. Through these mechanisms, probiotics and symbiotics alter the microbiota profile of individuals leading to loss of body weight and metabolic parameters associated with obesity.~Several studies have shown beneficial effects of using probiotics on body weight, glycemic control, improvement in lipid profile and blood pressure (BP). However, there are controversies about which are the best strains for this purpose. There are five systematic reviews currently published with or without meta-analysis that address the effect of using different probiotics on body weight. Among the strains associated with weight loss and/or adiposity, L. plantarum associated with L. rhamnosus and hypocaloric diet stand out; L. plantarum with L. curvatus; L. gasseri; L. amylovorus; L. acidophilus and L. casei associated with phenolic compounds; or Lactobacillus mix.
It is already known that dysbiosis, that is, qualitative and quantitative changes in the composition of the intestinal microbiota, can be associated with the development of a series of intestinal and extra-intestinal disorders. Dysbiosis is reported in irritable bowel syndrome, inflammatory bowel disease, colorectal cancer, allergic diseases, non-alcoholic steatohepatitis, arteriosclerotic diseases, neurological diseases and metabolic syndromes, mainly diabetes and obesity. Among the many factors that play a key role in obesity, a number of studies show the intestinal microbiota as an important contributor. Many studies carried out with probiotics have shown that their administration can be effective in the prevention and treatment of obesity. Furthermore, it is found that benefits for body weight, abdominal adiposity, anthropometric measurements and body composition are often associated with favorable metabolic effects.