Based on the article published in last edition’s Weight Loss column, we know there’s a strong link between weight management and our gut bacteria. We also know that probiotics have been associated with positively altering the gut microbiome. So, is it safe to say that supplementing with a probiotic can help us lose weight? Let’s take a look at the research.
In 2015, a systemic review and meta-analysis published in Nutrition Research identified 4 of 368 studies that were randomized controlled trials with adequate data assessing the efficacy of probiotic supplementation as a weight loss treatment. Results found no significant effects of probiotics on body weight or body mass index (BMI) when compared to placebo. Yet, researchers called for more “rigorously designed” randomized controlled trials with larger sample sizes to draw more accurate conclusions.
Fast forward three years to a review and meta-analysis study published in Obesity Reviews. The study looked at the impact of probiotic supplementation on body weight, body mass index (BMI), fat mass and fat percentage in overweight and obese subjects. This time, the analysis included 15 studies and 957 subjects (63% women) and an intervention timeframe of between 3 and 12 weeks. Researchers found that probiotic supplementation resulted in more body weight and fat lost when compared to placebo: the probiotic group experienced a 0.6-pound increase in weight loss and a 0.6% increase in fat loss. Although statistically significant, these results are pretty minimal and clinically irrelevant.
For a more focused look at the effects of probiotics on weight loss, a 2017 review assessed the impact of Lactobacillus on body weight and body fat in overweight subjects. 14 randomized controlled trial studies were included in the analysis. Of the 14 studies, 9 showed that Lactobacillus supplementation resulted in decreased body weight and/or body fat, 3 showed no effects, and 2 resulted in weight gain. Researchers concluded that positive results were strain dependent and were most evident in the following combinations:
- Lactobacillus plantarum and Lactobacillus rhamnosus when combined with a hypocaloric diet (more calories are burned than consumed)
- L. plantarum with Lactobacillus curvatus, Lactobacillus gasseri, Lactobacillus amylovorus, Lactobacillus acidophilus and Lactobacillus casei with phenolic compounds
- Multiple species of Lactobacillus
In taking a detailed look at the studies analyzed in the review, differences in weight and body fat loss between the probiotic and placebo groups, while statistically significant, were quite minimal.
While we all (including me!) dream of a magic pill to help us reach our health and weight loss goals, that’s magical thinking, and even if such a pill did exist, probiotic supplements are most likely not it. As illustrated above, while a handful of studies do show that probiotic supplementation can result in a couple extra pounds lost over a period of time, the larger body of scientific evidence tells us that probiotic supplementation doesn’t make a significant impact on weight loss or body fat reduction.
If you do choose to take a probiotic for weight loss, keep in mind that the probiotic bacteria in your pill is only as powerful as the food you feed it. And the bottom line is that focusing on a plant-based diet rich in prebiotic fiber is the best and quickest way to increase your gut garden’s diversity for optimal weight management.