The Best Probiotics for Weight Loss

Probiotics reset that all-important bacterial balance in our guts. Now, a growing body of research suggests that some probiotics may help us win the battle of the bulge.

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Probiotics 101

Most of us have heard of probiotics; they help restore the balance of good versus bad bacteria in the digestive system. When gut balance is out of whack, you may feel bloated, be constipated, have diarrhea, or experience many other digestive ills. Resetting your gut balance with probiotics may improve these—and many other aspects of health as well. A healthy gut microbiome might even add years to your life.

Woman standing on scale, close-up of legs.
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Probiotics for weight loss: evidence mounts

Exactly how probiotics may encourage weight loss is not 100 percent clear, but the evidence is building. “There are a lot of bits and pieces of preliminary evidence that our gut biome and by extension, manipulating it by way of probiotics, may have a positive effect on weight management,” says Scott Kahan, MD, the director of the National Center for Weight and Wellness in Washington, DC. In one interesting mouse study, animals underwent weight-loss surgery or a sham procedure, and as expected, the mice who had the real surgery lost weight. But then the researchers transplanted bacteria from the gut of the weight-loss surgery group into the guts of mice that didn’t—and then they lost weight too! “In a few years, we will know a lot more about the gut microbiome and how to manipulate it with probiotics for weight loss,” predicts Dr. Kahan.

gloved hand holding lab plate with bacteria and swab

Two types of gut bacteria linked to your weight

To understand the potential affects of probiotics on weight loss you need to start with an understanding of the key players. There are two first-families of bacteria in the gut: Bacteroidetes and Firmicutes. “Lean individuals have a higher proportion of bacteria from the Bacteriodetes family, while obese individuals have more from the Firmicutes family,” says Will Bulsiewicz, MD, a gastroenterologist in Mount Pleasant, SC. “The implication is that by modulating our gut flora to maximize Bacteroidetes and minimize Firmicutes, we can optimize healthy energy harvesting from our food and kick our obesity problem to the curb.” Put another way: “If we choose the right blend of bacteria, the scale can tip in our favor,” he says.

But which are the best probiotics for weight loss?

weight scale
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Lactobacillus rhamnosus

This member of the Bacteroidetes family may be the single best probiotic for weight loss. When researchers out of Université Laval in Quebec, Canada placed 125 overweight men and women on a 12-week weight-loss diet, followed by a 12-week period aimed at maintaining body weight, the women who took two probiotics from the L. rhamnosus family daily lost twice as much weight, compared with their counterparts who did not take probiotics. (The probiotics did not affect weight loss in men.) Look for L. rhamnosus on the label of dairy products or supplements—and then learn the best way to store your probiotics.

woman with measuring tape around her stomach

Lactobacillus gasseri

Another potential winner in the Lactobacillus family is L. gasseri, which has been associated with reductions in body weight and fat deep inside the abdomen. One recent randomized, placebo-controlled trial (albeit a small one) found that participants taking high doses of L. gasseri for 12 weeks lost more abdominal fat than those who took the placebo. The best probiotic will have diversity, says Dr. Bulsiewicz. “The ideal probiotic would feature the Bacteroidetes family, specifically several types of Lactobacillus bacteria including L. gasseri,” Dr. Bulsiewicz says. “A perfect example of this is the Advanced Gut Health Probiotic by Genuine Health. It includes ten types of Lactobacillus including L. gasseri. It also has five additional Bacteroidetes bacterial strains.”

two glasses of strawberry yogurt with spoon

Lactobacillus fermentum, Lactobacillus amylovorus

Among the numerous probiotics for weight loss listed above, there are also L. fermentum and L. amylovorus—two more strains that can help you shed pounds. In one small study, participants who ate yogurt that contained L. fermentum or L. amylovorus lost more body fat during a six-week period than dieters who didn’t. (P.S.: Animal research suggests probiotic-rich foods like yogurt may also help improve mental health.)

head of cabbage

Good for gut health: prebiotic foods

Prebiotics are plant carbohydrates such as inulin and certain saccharides that feed good-for-you bacteria in your gut. Even the best probiotic for women could get a boost from having plenty of this precursor around. Foods high in prebiotic fiber include soy beans, whole-wheat, asparagus, artichokes, onions, and leeks—plus some of these six gut-friendly foods.

spoon full of granulated sugar over a bowl of sugar

Bad for gut health: fake sweeteners

The best probiotics and foods restore bacterial balance, but others things disrupt it. And one culprit may be artificial sweeteners, says Dr. Kahan. One 2014 study in mice found that when mice ate certain zero-calorie sweeteners, the numbers and types of bacteria in their guts changed—and not for the better. Mice in the study who were fed real sugar did not experience these negative changes.

pumpkin, cauliflower, chard, leeks, broccoli, onion, garlic, and apple
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Common sense advice on probiotics for weight loss

One clue you may benefit from a probiotic: If you’ve recently taken antibiotics. Antibiotics destroy many strains of gut bacteria, including helpful ones; so next time you are prescribed antibiotics, ask your doctor if you should take probiotics at the same time. “It’s also smart to eat in ways that promote a healthy gut,” says Dr. Kahan. Diets rich in fruits, vegetables, whole grains, and beans tend to promote healthy gut microbiome, he says.

  • Scott Kahan, MD, director, National Center for Weight and Wellness, Washington, DC.
  • Science Translational Medicine: "Conserved Shifts in the Gut Microbiota Due to Gastric Bypass Reduce Host Weight and Adiposity."
  • Will Bulsiewicz, MD, gastroenterologist, Mount Pleasant, SC.
  • British Journal of Nutrition: "Effect of Lactobacillus rhamnosus CGMCC1.3724 Supplementation on Weight Loss and Maintenance in Obese Men and Women."
  • Journal of Medicinal Food: "Lactobacillus gasseri BNR17 Supplementation Reduces the Visceral Fat Accumulation and Waist Circumference in Obese Adults: A Randomized, Double-Blind, Placebo-Controlled Trial."
  • Journal of Functional Foods: "Lactobacillus fermentum and Lactobacillus amylovorus as Probiotics Alter Body Adiposity and Gut Microflora in Healthy Persons."
  • Academy of Nutrition and Dietetics: "Prebiotics and Probiotics: Creating a Healthier You."
  • Nature: "Artificial Sweeteners Induce Glucose Intolerance by Altering the Gut Microbiota."
Medically reviewed by Michael Spertus, MD, on August 26, 2019

Denise Mann, MS
Denise Mann is a freelance health writer whose articles regularly appear in WebMD, HealthDay, and other consumer health portals. She has received numerous awards, including the Arthritis Foundation's Northeast Region Prize for Online Journalism; the Excellence in Women's Health Research Journalism Award; the Journalistic Achievement Award from the American Society for Aesthetic Plastic Surgery; National Newsmaker of the Year by the Community Anti-Drug Coalitions of America; the Gold Award for Best Service Journalism from the Magazine Association of the Southeast; a Bronze Award from The American Society of Healthcare Publication Editors (for a cover story she wrote in Plastic Surgery Practice magazine); and an honorable mention in the International Osteoporosis Foundation Journalism Awards. She was part of the writing team awarded a 2008 Sigma Delta Chi award for her part in a WebMD series on autism. Her first foray into health reporting was with the Medical Tribune News Service, where her articles appeared regularly in such newspapers as the Detroit Free Press, Chicago Sun-Times, Dallas Morning News, and Los Angeles Daily News. Mann received a graduate degree from the Medill School of Journalism at Northwestern University in Evanston, Ill., and her undergraduate degree from Lehigh University in Bethlehem, Pa. She lives in New York with her husband David; sons Teddy and Evan; and their miniature schnauzer, Perri Winkle Blu.