Research on probiotics is still relatively new and growing. Scientists believe that there is a link between reduced bacterial gut diversity and obesity. An unhealthy digestive system may lead to dysbiosis, which refers to an imbalance in the gut microbes.
When too many harmful microorganisms grow, there may not be enough of the helpful bacteria available to keep these harmful organisms in check. It also typically means the diversity of bacteria in the gut is lower.
Research published in 2013 suggests that gut dysbiosis contributes to the development of obesity, though it may not be the underlying cause.
As the author of a 2015 study notes, people at a healthy weight and people with obesity show marked differences in their gut flora.
Their research found that changing the gut flora in animals caused them to lose or gain weight accordingly. However, in humans, changing the gut flora did not result in weight loss or gain.
This evidence does suggest, however, that there is a shift in a person's gut flora when they gain weight. While changes are associated with obesity, they do not seem to be the underlying cause.
The researcher identified the following factors that can change a person's gut flora from a thin to an obese pattern:
a high-fat diet
a high-calorie diet
the use of artificial sweeteners
a disrupted diurnal rhythm
There is a small body of evidence suggesting some probiotics may help people lose weight.
Research studied the effects that one type of probiotic, Lactobacillus rhamnosus, had on people with obesity.
Women who took the probiotic supplement lost more weight during the study than women who took a placebo. Additionally, the group taking a probiotic supplement continued to lose more weight in the weight-maintenance stage, after they finished dieting. The same effects did not occur in men,