Can Probiotics Lead To Weight Loss?

Weight loss

We’ve all heard that probiotics, the so called “good” bacteria, benefit our well-being beyond just our digestive health. Probiotics keep the proliferation of harmful bacteria (pathogens) in check, aid in nutrient absorption, and support healthy immunity. A recent study links one strain of probiotics to another pressing world-wide concern: weight loss. The Canadian study, published in the April 2014 issue of the British Journal of Nutrition, claims that probiotics have the ability to not only help you lose weight, but also keep it off. One catch—this effect appears to be sex-specific, with significant results seen only in women.

Study Overview

In this double-blind, placebo-controlled, randomized trial, study authors recruited 125 obese, but otherwise healthy people for a total of 24 weeks. The study was separated into two distinct stages:

  • First 12 weeks—participants were put on a “supervised, calorie-restricted weight-loss diet.”
  • Second 12 weeks—participants were put on a weight-maintenance program with a personalized diet plan, but were not limited to any calorie restrictions.

One half of the study’s participants received two daily pills of Lactobacillus rhamnosus, about the same dosage of probiotics in a single serving of yogurt, while the other half was administered placebo.

Why the separation of the 24-week study into two 12-week periods? The first 12 weeks were meant to assess the efficacy of probiotics and helping people lose weight. The second 12 weeks—where no calorie restrictions were enforced—were a test of how well the probiotics worked to keep the weight off and promote further weight loss.


The study showed that probiotics had a significant effect not only on initially losing the weight, but a dramatic effect on keeping it off and even promoting further weight loss. Results showed that:

  1. During the first 12 weeks, women who took probiotic supplements lost an average of 9.7 pounds while those who took placebo only lost 5.7 pounds.
  2. During the second 12-week period, women who took probiotics kept shedding the pounds while opposite changes were observed in the placebo group.

Body weight reduction was accompanied by reductions in fat mass and lower levels of circulating leptin, an anorexigenic hormone implicated in the regulation of metabolism and appetite. It is thought that obese individuals are leptin-resistant. No significant body weight or fat mass changes were noted in men. While larger scale studies are needed to further understand the magnitude of probiotics’ effect on weight loss, the current study indicates that beneficial bacteria may be a promising way of helping women battle obesity.