Can Probiotics Help You Lose Weight? Here's The Science

Probiotics for Weight Loss

Illustration by Jenny Chang-Rodriguez

Your gut is a teeming warehouse of trillions of bacteria—some of those are good and protective while others are destructive. When everything is functioning optimally, your body is able to maintain a healthy balance. But it doesn't take much to throw it out of whack—think illness, medication, or simply a change in diet. When the bacteria in the intestinal tract starts growing in the wrong direction, it not only can affect your health, but it can also contribute to weight gain or make weight loss more difficult because your gut bacteria are intricately connected with both your metabolism and digestive system.*

How do you put up a good defense? A probiotic supplement of good bacteria can help maintain or help restore a healthy bacterial balance to your digestive system.* Supplements of certain probiotic strains, such as Lactobacillus and Bifidobacterium, battle with bad bacteria for space and, when victorious, your health will benefit.*

Does gut health influence weight?

What does your gut microbiome, the collection of trillions of bacteria living in your intestines, have to do with weight maintenance? More than you might think. Research has shown that the bacterial makeup in individuals who are obese is less diverse than in individuals who are lean.

But it presents a chicken-or-the-egg question—does the imbalance cause weight gain or does the extra weight somehow change the balance of bacteria? Renowned integrative physician Robert Rountree, M.D., thinks the evidence is clear, "There is no question that the bacteria in our gut can affect our weight."* He cites animal studies, in which obese mice are given a fecal transplant from lean mice and, consequently, lose weight and body fat.*

This might be due to how gut bacteria interact with our cells and digestive process. One study found that simply overeating can tip the balance in favor of bad bacteria. The problem? As Rountree explains it, "Certain bacteria are better at extracting energy from food than others." This means these bacteria can harvest even more calories from the increased intake of food, to be turned into energy and body fat.* A double weight-gain whammy, if you will.

In addition, gut bacteria play a role in appetite regulation and satiety.* When the "good" bacteria outnumber the "bad," the levels of short-chain fatty acids increase in the gut, triggering the production of hormones that regulate appetite.* So, if these hormones are out of balance, then you might not get the signal that you are full.

The result is a vicious weight-gain cycle—you overeat and the bad bacteria increases in your gut, possibly increasing body fat and lowering levels of short-chain fatty acids that would otherwise help control your appetite, causing you to eat more, which increases the bad bacteria, which...well, you get the idea.*


So, can a probiotic supplement help with weight maintenance?*

Although more research is needed to understand the complex interactions between the microbiome and weight maintenance, Rountree says, "I think we are on the verge of discovering what the bacteria might be what could be causing this obesity problem," and new studies are zeroing in on the possible benefits of probiotic supplements to aid in weight maintenance.* 

In a study of 125 obese men and women, published in British Journal of Nutrition, it was found that probiotic supplementation helped obese women lose weight and maintain their weight loss over a 24-week period while following a reduced-calorie diet.* The women taking the probiotic supplement lost significantly more weight than women in the control group, who also followed a reduced-calorie diet but did not take the probiotic supplement.* 

Another study, this one of 90 overweight and obese adults, found that taking a probiotic supplement for 12 weeks had a favorable effect on participants' visceral fat—the fat that accumulates near the liver, stomach, and intestines and increases the risk for many diseases.* 

These and other studies have used different combinations of probiotic bacteria, making it tougher to pinpoint which one(s) might be most helpful for weight maintenance.* Still, a 2018 analysis of several probiotic studies on weight concluded that probiotics are "essential tools in the [management] of obesity and can lead to significant decreases in BMI, weight, and fat mass."*

The best probiotic strains for weight maintenance.



Four targeted strains to beat bloating and help reduce abdominal fat.*

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There are thousands of strains of bacteria that make up the trillions roaming around in your gut. Although researchers identify these strains with a combination of letters and numbers, supplement labels don't always list the strains of bacteria they contain—typically you'll find only the group and species—such as Lactobacillus rhamnosus or Bifidobacterium lactis

Although more research is needed to identify the specific strains and dosages of probiotic bacteria that might best help your weight-maintenance efforts, there are a few probiotic strains that show real promise.* The most well-researched strains for weight maintenance include:

Each of these strains has been specifically studied for their impact on weight and has been found to have favorable effects on body fat, waist circumference, visceral fat, and glucose control.*


Don't forget about diet and lifestyle.

If you take a probiotic supplement, then it can offer a weight-maintenance advantage, but that alone won't be enough to knock off the extra pounds.* Eating less and moving more are still the pillars of weight loss success. 

Bottom line.

The research on probiotics and weight is just getting started. But initial findings are promising. Scientists have already identified several strains that can support weight management.* These strains, which include Bifidobacterium lactis B420 and Lactobacillus gasseri BNR17, have been found to have favorable effects on body fat, waist circumference, visceral fat, and glucose control.*


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