Probiotics for Weight Loss: Is There a Link?

In recent years, more people have become curious about the potential of probiotics to improve our health and wellbeing. These are foods and supplements containing live microorganisms that reinforce the population already living in our guts.

Probiotics are perhaps best known for their positive influence on digestion. However, research suggests that they could benefit us in several additional ways. Could maintaining a healthy body weight be one of them?

A growing number of people are now classified as overweight or obese. Therefore, interest in probiotics for weight loss is on the rise. Here’s our complete guide.

Probiotics and Weight Loss

Our digestive tracts are home to approximately 100 trillion microbes, most of which are bacteria. They are collectively known as the gut flora or microbiome.

These microscopic organisms play a vital role in many of our physiological functions. From digestion to immunity, the gut microbiome’s importance cannot be overstated. Some experts have even linked imbalances to mental health conditions like depression.


Scientists have also proposed a relationship between the microbiome and body weight. It has led some to explore whether probiotics could be an effective weight-loss tool.

Below, we will discuss some of the latest research on probiotics and weight loss. But first, let’s explore the link between gut health and weight.

The Gut Microbiome and Body Weight

The gut microbiome is involved in many of our digestive and metabolic processes. They include carbohydrate fermentation, energy uptake and storage, hormone release, and neurotransmitter activity.

Some gut bacteria convert complex carbohydrates that we cannot digest into chemicals called short-chain fatty acids (SCFAs).

SCFAs have a crucial function in the metabolic process. They regulate energy expenditure and the synthesis of fats. They also influence the hormones involved in glucose tolerance, hunger, and satiety.

Researchers first discovered the link between the microbiome and body weight while experimenting on mice. They noticed that transferring gut bacteria from obese to lean animals resulted in an overall increase in weight.

Research suggests that people who are overweight or obese have different gut flora from those who are not.

Human studies have produced less consistent results. However, it seems that people who are overweight or obese have different gut flora from those who are not.

Most experts agree that overweight people have a higher ratio of bacteria called Firmicutes compared to Bacteroidetes. They may also have a reduced diversity of microorganisms in their guts overall.

These changes are likely the result of eating a low-fiber, high-fat, high-sugar diet, which is associated with weight gain in itself. The imbalance may also alter the way the body utilizes and stores energy, further increasing the rate at which it accumulates fat.

So, where do probiotics fit in? Let’s take a look at the potential benefits of increasing good gut bacteria for weight loss.

Probiotics Supplements for Weight Loss

The apparent relationship between the microbiome and body weight has led some people to wonder about probiotics’ role. Could they possibly act as some kind of gut bacteria weight loss supplement?

Unfortunately, the answer is not straightforward. Many different factors can influence probiotic supplements’ efficacy, including:

  • The specific bacterial strain or strains included
  • How many colony-forming units (CFU) are in the product
  • The consumer’s diet (overall composition and energy content)
  • Physical activity
  • Use of antibiotics and other medications
  • Individual physiology (age, gender, etc.)

That said, much of the research to date has produced positive results. We will discuss some relevant studies in the next section.

Probiotics and Weight Loss Studies

A 2020 study included 220 participants aged 30–65 years with a body mass index (BMI) between 25 and 34.9kg/m². They took a probiotic or placebo once daily with food for six months while maintaining their usual diet and lifestyle.

The probiotic contained several bacterial species, including Lactobacillus acidophilus, Lactobacillus plantarum, Bifidobacterium bifidum, and Bifidobacterium animalis subspecies lactis. The daily dosage was 50 billion CFU.

After three months, the researchers observed limited changes. However, after six months, the subjects in the probiotic group displayed greater weight loss than the control group. The most significant decreases were in participants with high cholesterol, who also experienced reductions in harmful low-density lipoprotein (LDL) cholesterol.

The probiotic group also showed greater waist circumference and waist-to-height ratio reductions and reported improved quality of life.

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Lead researcher D.R. Michael followed up with another study in 2021. This time there were 70 subjects aged 45–65 with a BMI between 25 and 29.9kg/m². They took the same probiotic blend or a placebo, this time for nine months.

The results confirmed those of the team’s previous probiotics weight loss research. Those in the treatment group displayed more significant reductions in body weight, waist circumference, and hip circumference than the control subjects.

These findings align with a 2017 review of 15 studies and 957 participants with a mean BMI of 27.6kg/m². The authors found that probiotics reduced body weight and fat percentage vs. placebo when taken for 3–12 weeks. However, the effect sizes were small, meaning that further research is warranted.

Can Probiotics Help You Lose Weight?

The current evidence suggests that using a probiotic to lose weight could be beneficial. However, many other factors contribute to the success of any weight loss program.

The most important of these is ensuring that energy expenditure exceeds energy intake. This means that individuals should consume fewer calories than they burn each day.

However, some weight-loss diets may do more harm than good in the long run. For example, fad diets that involve cutting out entire food groups can negatively impact microbiome diversity.

Therefore, eating a balanced diet and increasing calorie expenditure by exercising is much healthier and more sustainable.


Probiotics’ effectiveness also depends upon the quality of the product and the consumption method. For example, there are many different probiotic foods that could help to improve the microbiome’s makeup. However, many commercial products are pasteurized, meaning that they contain insufficient quantities of live microorganisms.

Therefore, taking a probiotic supplement may be a better option. Providing the product contains a reasonable CFU count and several bacterial strains, it could contribute to overall gut health and weight loss.

However, it is also necessary to consume prebiotic foods to ensure that probiotics can work optimally. Prebiotics are indigestible compounds that the microbiome uses as fuel. Most fresh fruit and vegetables contain plenty of prebiotic compounds in the form of dietary fiber. Whole grains, mushrooms, honey, and even dark chocolate are also excellent sources.

Finally, some probiotic supplements already contain prebiotics to maximize their effects. These products are called synbiotics, and they are a good choice for anyone who struggles to eat enough prebiotic foods.

Bottom Line on Probiotics for Weight Loss

The gut microbiome appears to contribute to how readily an individual gains or loses weight.

Imbalances in this complex system can alter one’s metabolism, leading to increased energy uptake and fat storage. This relationship has led many scientists to investigate the link between probiotics and weight loss.

Probiotics could potentially help to reduce body mass index, waist circumference, and more.

Probiotics could potentially help to reduce body mass index, waist circumference, and more. However, it is essential to choose a high-quality product to reap the benefits. Moreover, individuals hoping to lose weight should eat well and increase physical activity rather than relying on probiotics alone.

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