Do probiotics make you gain weight? Yes, some do

Weight loss goals- woman stepping on home scale to check weight loss, do probiotics cause weight gain

So, you started your new probiotics, and after a little while, the scale keeps inching up. You might be wracking your brain and thinking that it couldn’t possibly be the probiotics. But the truth is: it’s a real possibility. Some popular strains of probiotics can definitely make you gain weight.

I don’t get it. How can probiotics affect my weight?

If the idea that probiotics can make your jeans tighter is a shock, we completely understand. But don’t let your surprise convince you to ditch your bottle of probiotics. At least not yet. The fact is, a lot of us start probiotics because we want to support our gut health—and that’s a good thing.

Weight loss from probiotics

First, not all probiotics lead to weight loss or weight gain. So, instead of dropping probiotics all together, we recommend taking a sec to choose strains that fit with your health and fitness goals.

If you’re wanting to lose weight, certain probiotics can help by reducing inflammation in your body. So, how does less inflammation equal weight loss? It has to do with your sensitivity to the hormone insulin. When your insulin sensitivity is good, it helps keep your blood sugar levels in check. Good blood sugar levels mean that, instead of storing extra glucose as fat (hello, weight gain!), our bodies use it for energy. This helps some people lose weight—or at least lower your chances of gaining it.

Another reason some probiotics help you drop a few pounds? They increase levels of the hormone leptin—and that’s perfect if you’re trying to maintain or lose weight. Higher levels of leptin suppress your appetite. It lets your body know when you don’t need any more food and signals that you’re satisfied and good on energy. As a result, you end up eating fewer calories.

Want to learn more about gut health and hormones? Check out Dr. Nicole Lewis’ article on gut health and hormones here. Or, take a peek at registered dietitian Wendie Taylor’s advice on how stress affects your gut.)

Weight gain from probiotics

Even though some probiotic strains promote weight loss, others do the opposite. With weight loss, the gut microbiome changes from your probiotics create hormonal fluctuations that help you shed pounds. But other probiotics signal hormones that lead to weight gain. One way this happens is through insulin levels. Rather than improving insulin sensitivity, some probiotics contribute to insulin resistance. When insulin resistance occurs, your body takes extra sugar and stores it as fat. This can pack on the pounds pretty quickly—especially if your diet is high in sugars/refined carbohydrates. Another way some probiotics lead to weight gain is by increasing levels of the hormone ghrelin. Ghrelin is your hunger hormone—it makes you want to eat, and sometimes more than your body needs.

Interested in learning more about ghrelin, leptin, and weight loss? Check out Dr. Orlena’s article right here on

So, which probiotic strains should I stay away from?

Whether you’re eyeing weight gain or weight loss, you’ll want to pay extra close attention to probiotic products that contain strains of lactobacillus—which is a good portion of those on the market. Some strains help with weight loss, but others don’t. Specifically, studies have shown that the strain lactobacillus acidophilus comes with the risk of fairly significant weight gain. On the other hand, data shows that lactobacillus gasseri┬ástrains may be one of the best strains to help with weight loss. Other strains that are great for controlling weight? Lactobacillus rhamnosus and bifidobacterium lactis.

Do I need to talk to a pro before starting probiotics?

Regardless of whether or not you’re in good health, talking to a qualified healthcare professional before starting probiotics is a great idea. Even though probiotics are available over the counter, not everyone should take them. If you’re pregnant or nursing or immunocompromised—whether from a health condition or treatment such as chemotherapy—you need to work closely with a physician and registered dietitian.