Do Probiotics make you gain weight?

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Weight loss is becoming a common goal as society turns overweight in the Western World. But there is often confusing information about products and foods, and studies often claim conflicting results. In the field of probiotics, there’s much ongoing research, and not everything is understood and wholly studied. But there are some early understandings about the association between probiotics and weight management that deserve a short review.

In this article, we will cover the basic aspects of how probiotics can modulate your weight, always keeping in mind that the best strategy for weight loss is achieving a negative calorie balance, which is achieved much faster through a combination of diet and physical activity. Can probiotics become an additional booster? Are they helpful for underweight patients instead?

Will you gain weight or lose weight with probiotics?

Probiotics are useful and potential treatment tools under ongoing research. One of the best things about these supplements and foods is that they do not have side effects and can be apparently applied to various fields of preventative medicine. But sometimes the scientific studies about probiotics throw conflicting results.

According to research, applying probiotics in patients may result in either weight loss, weight gain, or maintenance of a healthy weight. It depends on three different variables that we will analyze further:

  • The gut microbiota of the host: As you will see, obesity has a pattern of gut microbiota, which may count as a dysbiosis. However, more research is needed to guarantee whether it is a cause or a result of obesity.
  • The strain of probiotics that is chosen: Certain probiotic strains appear to have a potential to increase weight gain by speeding up the absorption of nutrients. Other probiotics will have the opposite effect as they are proposed to display thermogenic potential.
  • Any other external factor that may be involved in the process: The diet, physical activity, additives and processing of probiotic foods may contribute to weight loss or weight gain, regardless of the strain or the baseline microbiota of the host.

Gut microbiota and obesity

According to recent studies about the gut microbiota, obese people have a different balance of microbes and microbial strains. The type of bacteria in the gut can influence at least two different aspects associated to weight gain:

  • Energy harvest: Probiotics may favor the uptake of energy and breakdown of nutrients, increasing the amount of calories we obtain from the same amount of food.
  • Nutrient absorption: Probiotics promote absorption of certain nutrients, and may even create new substances that will be absorbed into the bloodstream and modulate the metabolism of energy and other vital pathways for weight management.

Probiotics in prevention and treatment of obesity

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Moreover, studies have demonstrated that obese individuals have a slightly different microbiota compared to lean individuals. For example, they have an increased number of Staphylococcus bacteria and Escherichia coli strains, and there’s a reduction in Bifidobacterium strains.

This modulation has been found in many studies, but we still don’t know the cause. Is it that such modulation promotes weight gain? Or maybe that obesity itself changes our gut activity and creates the ideal environment to favor one group of bacteria instead of the other? We still don’t know the answer to those questions, but what we do know is that some probiotics can promote weight gain while others are associated with a more accelerated weight loss in patients under weight management programs.

Probiotics that promote weight gain

Some probiotics can be used to promote weight gain in underweight patients through an increase in energy harvest and nutrient absorption. Weight gain can also be an unexpected and undesired side effect in some instances.

For example, there are many types and subtypes of Lactobacilli strains, and they are widely popular in the world of probiotics. However, some of them may have a weight gain potential, especially Lactobacillus acidophilus. This bacterial strain may help underweight patients to gain weight or promote obesity in overweight patients. Thus, it is often administered to increase the size and weight of livestock in certain cases.

In other cases, people using probiotic foods should be aware of the ingredients before using them for weight loss purposes. Many people have the mistaken idea that all probiotic foods are healthy foods, or at least healthier than average. But that’s not always the case. Certain foods with probiotic strains do modulate gut microbiota but are overloaded with sugar and other food additives that contribute to weight gain. The most important example is yogurt, which comes in various presentations, sweetened and heavily flavored to improve the taste.

Using probiotics for weight management

Considering all of the above, if we want to use probiotics for weight management, we should understand the basics of the gut microbiota, the most important strains, and the external factors that may contribute to our goals.

Remember that obese individuals usually have a reduction of Bifidobacteria, which can be supplemented with probiotics. If you’re using Lactobacilli to lose weight, avoid L. acidophilus and use other strains such as Lactobacillus gasseri, which has been studied for a thermogenic potential that will metabolize fatty acids instead of increasing the harvesting of energy in the gastrointestinal system. And if you’re consuming probiotic foods, avoid heavily flavored and ultra-processed yogurt, which crosses the line of healthy foods due to an excessive dose of added sugars.

Finally, keep in mind that probiotics can be an additional boost to your weight management program, but do not replace the importance of physical activity and a careful and individualized diet.


Ejtahed, H. S., Angoorani, P., Soroush, A. R., Atlasi, R., Hasani-Ranjbar, S., Mortazavian, A. M., & Larijani, B. (2019). Probiotics supplementation for the obesity management; A systematic review of animal studies and clinical trials. Journal of functional foods52, 228-242.

Million, M., Angelakis, E., Paul, M., Armougom, F., Leibovici, L., & Raoult, D. (2012). Comparative meta-analysis of the effect of Lactobacillus species on weight gain in humans and animals. Microbial pathogenesis53(2), 100-108.

Mazloom, K., Siddiqi, I., & Covasa, M. (2019). Probiotics: How Effective Are They in the Fight against Obesity?. Nutrients11(2), 258.

Turnbaugh, P. J., Ley, R. E., Mahowald, M. A., Magrini, V., Mardis, E. R., & Gordon, J. I. (2006). An obesity-associated gut microbiome with increased capacity for energy harvest. nature444(7122), 1027.

About Simon Bendini 64 Articles
Hello, I'm an expert in all things Probiotics. I also live and breathe what I write about: I take Probioitcs EVERY day. I want to help you discover the benefits of them too. Enjoy my humble site.

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