Probiotics are live organisms that occur naturally in the gut. Many supplements and fermented foods also contain probiotics. Some people wonder if probiotics can help them lose weight.

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Taking a probiotic supplement may help keep the intestinal flora balanced and promote a healthy body by boosting the digestive and immune systems.

While the research is still in the preliminary stages, some information suggests that probiotics could help a person lose weight, or that poor gut health has links to obesity.

In this article, learn about probiotics and weight loss, including whether they work and how to use them.

There are many different microorganisms in and on the human body, mainly in the form of friendly bacteria. Researchers think that some of these bacteria may play a role in weight loss and gain.

In the gut, the beneficial bacteria help break down and digest food. They also help create nutrients and vitamins for the body to use. The probiotic bacteria feed on fibers and turn them into helpful compounds.

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 from 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 in The British Journal of Nutrition 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, however.

Another 2013 study looked at the effects of Lactobacillus fermentum and Lactobacillus amylovorus.

During the study, individuals who were overweight but otherwise healthy ate yogurt that contained these Lactobacillus strains for 6 weeks. At the end of this period, the participants had lost an average of 3–4% body fat.

Researchers have also examined effects of Lactobacillus gasseri for fat loss. In this study, people with extra belly fat who drank fermented milk products containing the helpful bacteria lost 8.2– 8.5% of their belly fat over 12 weeks.

However, when they stopped drinking the milk, all of this belly fat returned. This suggests probiotics can help people lose weight in some cases, but researchers still need to do more studies to back up this claim.

Low bacterial diversity may also influence obesity. For instance, the author of a 2015 review found that there is a link between low gut flora diversity and inflammation in the body.

Low microbial diversity may also be a risk factor for problems associated with obesity, such as metabolic syndrome and type 2 diabetes.

With these facts in mind, taking probiotics could benefit not just a person’s weight loss efforts, but their overall health.

The most common probiotics are from the groups Lactobacillus and Bifidobacterium. Each of these contain many different bacteria.

Probiotics may also contain other bacteria along with other organisms, such as the yeast Saccharomyces boulardii.

The more popular bacteria on the market and most studied for their health benefits include:

  • Lactobacillus acidophilus
  • Lactobacillus bulgaricus
  • Lactobacillus fermentum
  • Lactobacillus amylovorous
  • Lactobacillus gasseri
  • Lactobacillus rhamnosus
  • Bifidobacterium longum
  • Bifidobacterium bifidum

However, the gut contains hundreds of different types of microorganisms, totaling over 100 trillion microbes.

There is no evidence that one type of probiotic can help a person lose weight more effectively than any other kind.

There are two different ways a person can add beneficial probiotics to their regular diet:


There are many probiotic supplements available. These products typically include strains of Lactobacillus or Bifidobacterium bacteria. Sometimes they contain both.

Probiotic supplements are available for purchase in health food stores, pharmacies, and online.

Fermented foods

Many foods also contain these healthful organisms. Yogurt may be the most well-known dietary source of probiotics. Yogurt is milk which ferments with specific Lactobacillus or Bifidobacterium strains.

Other fermented foods that often contain helpful bacteria include:

  • kefir
  • sauerkraut
  • kombucha
  • fermented, raw cheeses
  • raw apple cider vinegar
  • kimchi
  • natto, miso, or tempeh

The National Center for Complementary and Integrative Health state that different probiotics may work in different ways, performing a wide variety of functions, including:

  • outcompeting harmful bacteria to keep the gut balanced
  • maintaining a healthful balance of helpful microorganisms
  • stimulating the immune system response
  • protecting the barrier of the digestive tract from harmful microorganisms

In addition to promoting healthy digestion, probiotics may have many other effects. Research from 2015 suggests that a healthy gut colony is important for numerous body functions, such as:

  • overall nutrition
  • growth
  • regulating the immune system
  • keeping the hormones balanced
  • regulating mood
  • promoting the proper growth of the nervous system

Research on probiotics is still relatively new and growing. Scientists believe that there is a link between reduced bacterial gut diversity and obesity.

Also, some evidence in humans shows that some probiotics, such as some Lactobacillus strains, may help people lose weight or body fat.

However, probiotics are not a guaranteed weight loss strategy. Experts think they could be one part of a comprehensive weight loss program. They will not replace diet and exercise efforts.

The best way to use probiotics for overall health and weight loss may be to include them in a nutritious, varied diet, rich in vegetables, fruits, and other whole foods.