The Truth of Whether Prebiotics Can Help With Weight Loss

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​​Most of us could do with losing some weight, it’s not just the obese who could do with losing excess fat around vital body organs.

Weighing too much puts greater strain on your body, makes everything feel like it takes more effort, and can put us at greater risk of diseases like hypertension, diabetes, high cholesterol, cardiovascular disease and cirrhosis if we don’t do something about it.

Many people like to stick to the calories-in versus calories-out method for weight loss, and while this is key, it’s not the whole story. 

If you’re a fan of this website, you probably already know quite a bit about the benefits of prebiotics and probiotics and what they can do for your overall health.

But this article is going to focus on whether prebiotics can help you to lose excess body weight. 

We’re going to cover:

  • Whether prebiotics can help with weight loss
  • The effect of bad bacteria on body weight
  • The weight loss benefits of using prebiotics
  • Can having a healthy gut microbiome prevent weight gain?
  • How to incorporate more prebiotics and probiotics into your diet
  • Answers to your most frequently asked questions

Please feel free to scroll ahead to any section that interests you.

Can Prebiotics Help with Weight Loss?

I love that I get to kick off this article with some good news! 

It has long been established that probiotics are associated with maintaining a healthy body weight, but it also turns out, according to research, that prebiotics can also help with weight loss.

For those of you who get mixed up with the differences between probiotics and prebiotics, here’s a quick recap for you…

Probiotics are living strains of bacteria that add to the population of good bacteria in your digestive system. While prebiotics are specialized non-digestible plant fiber that acts as food for the good bacteria, stimulating its growth. 

There are two main functions of prebiotics in your body:

  1. They produce short-chain fatty acids (SCFA) through the process of fermentation. These SCFAs then go on to act as important chemical messengers throughout the body.
  2. They promote the growth of probiotics in your gut. In particular, they aid the growth of bifidobacteria, lactobacilli, and also some anaerobic bacteria.

Examples of prebiotic fiber include inulin and oligofructose, which naturally occur in certain plants, but are also known to be added into some foods to boost both flavor and texture. And of course, you can also obtain prebiotic and probiotic supplements containing these too.

Let’s now examine how bad gut bacteria can affect your body weight.

The Effect Of Bad Gut Bacteria On Body Weight

Your gut contains many microorganisms such as bacteria and yeast. And while many of these benefit the body, there are, unfortunately, ones that don’t. And when such “bad bacteria” begin to multiply, this can produce an imbalance of good and bad bacteria. This is known as dysbiosis. 

Dysbiosis can be caused (at least in part) to diets that are high in sugar and processed foods. Other factors include the use of antibiotics, medications that alter bowel motility, and physical and emotional stress.

Dysbiosis can lead to bloating and inflammation, and has also been directly linked to excess body weight and belly fat. 

There are two main types of microorganisms in your gut. These are bacteroidetes and firmicutes.

There have been some studies that suggest that a disproportion of firmicutes in your gut’s microbiome can contribute to obesity in both children and adults.  This research is not yet definitive.

It is, however, accepted that the composition of microorganisms in your gut plays a role in the metabolic processes which affect your body weight.

It does so in three different ways. Regulating the hormones that affect your appetite, regulating the hormones that affect your blood sugar, and by determining how energy is used within your body. Let’s go into more detail…


As we all know, feeling hungry is what often prompts us to eat more, and is one of the biggest contributing factors in gaining too much weight.

In a healthy body, there will be signals from the gut to the brain to let you know when you are full and that it’s time to stop eating. However, intestinal dysbiosis causes a glitch in this system…

Peptide YY (PYY) and glucagon-like peptide 1 (GLP-1) are two “satiety hormones” which are supposed to let your brain know when you have eaten enough. However, bad bacteria in your gut can suppress these hormones.

Peptide YY has two main functions. It slows the movement of food through your small intestine for better absorption of nutrients, and it helps you to feel satisfied. But, how much PYY is released into the bloodstream depends on the composition of your gut bacteria. 

One study showed that when people’s PYY levels drop (due to antibiotic treatment), their appetite and food intake goes up.

And at the same time, there was a shift in the composition of their gut’s microbiome to contain higher levels of bacteria associated with obesity, compared to levels before the treatment began.

GLP-1, which functions in the same way as PYY is also produced in lower amounts in the body when bad bacteria are too prevalent in the intestinal microbiome.

Blood Sugar

Dysbiosis, and the accompanying disruption of PYY and GLP-1 hormones also impacts blood sugar levels, since these hormones help regulate insulin production and blood glucose levels.

When the secretion of these hormones is less than optimal, you can also get inflammation of the bowels and metabolic issues such as heart disease and type 2 diabetes.

Excess weight when combined with blood sugar imbalances and intestinal dysbiosis can become a downward spiral.

With each issue exacerbating the others, you get stuck in a cycle where it becomes increasingly difficult to lose weight.

Central Nervous System

The gut and the brain communicate with each other via the gut-brain axis. This has implications for how mood and temperament affect your body weight.

For example, emotional states such as depression and anxiety are linked to dysbiosis. This affects how much you eat, how much you move, and how your body uses its fuel.

IBS Overview: Symptoms, Causes, Diagnosis, and TreatmentIrritable bowel syndrome, known commonly as IBS, is a good example of a condition which develops when there are problems with how the gut and the nervous system interact.

Immune System

Your gut plays a very significant role in your immune system. Good bacteria in your gut helps to protect you against pathogens, but it also helps your immune system to distinguish between real threats, such as Covid-19, and perceived threats, such as seasonal allergies.

So, dysbiosis can leave you more prone to illness. It can give you an overactive immune system, which leaves you feeling drained, make your joints feel achy, and make you dread any exercise.

The Weight Loss Benefits Of Using Prebiotics

The effect of prebiotics in weight loss is many-fold. Let’s look at each of the influences.

Prebiotics Fill You Up

Prebiotics are basically non-digestible fiber, which means they help to fill you up faster. And the more fiber in your gut, the less desire you’ll have for more high calorie food.

Despite prebiotics being considered a carbohydrate, they don’t get absorbed into the blood, so it only provides about 2.5 calories per gram.

Prebiotics Reduce The Amount Of Fat Absorbed

In addition to making you feel full, prebiotics can also reduce the portion of fat that your body absorbs from your food. 

Prebiotics Produce SCFAs

When prebiotics get to the large intestine, they undergo a process of fermentation, where they are converted into short chain fatty acids (SCFA) which help with weight loss.

These SCFAs have two effects. They suppress your appetite by signaling to the brain that you are full, and they help all the good bacteria in your gut to thrive, which can prevent or correct dysbiosis. This could break the dreaded cycle of weight gain caused by dysbiosis.

Prebiotics Work Synergistically With Gut Bacteria And Probiotics

Although prebiotics alone can help with weight loss, they also work in harmony with your gut bacteria, and any probiotics you take to further support your weight loss.

Some Prebiotics Support Good Anaerobic Bacteria

Some prebiotics provide food for good anaerobic bacteria in the gut. Examples of this anaerobic bacteria include Akkermansia muciniphila and Faecalibacterium prausnitzii.

These bacteria cannot be made into supplements because they die in the presence of oxygen. 

These bacteria play an important role by producing a SCFA called butyrate, which has several important functions in the body.

Too little of these bacteria has been associated with a number of conditions, including being overweight. 

Does Having A Healthy Gut Microbiome Help To Prevent Weight Gain?

I just love being the bearer of good news! 

When you have a healthy gut microbiome, you are alerted to when you are full, and your blood sugar should remain stable.

A healthy gut microbiome also prevents issues with your digestion, keeps inflammation in check, and protects against harmful pathogens.

Maintaining a healthy gut microbiome requires the right conditions for the good bacteria to thrive. To achieve this, you need a diet that’s high in fiber, while at the same time being low in refined sugars and processed foods.

And unsurprisingly, these are also common recommendations for maintaining a healthy weight anyway.

A healthy balance of microorganisms in your gut is associated with better life-long weight management. So, it’s certainly worth considering your gut health if you want to prevent any unnecessary weight gain.

Especially when you consider how much easier it is to prevent weight gain compared to shedding it once it’s there. 

How To Incorporate More Prebiotics And Probiotics Into Your Diet

The good news is that it’s easy to introduce more prebiotics into your diet. Here are some ideas of what you can include when possible:

  • Leafy greens, such as spinach
  • Root vegetables, such as onions, garlic, leeks, asparagus, and chicory
  • Grains, such as oats, barley and brown rice
  • Legumes, such as lentils and beans
  • Fruits, such as apples, tomatoes, bananas, berries, and avocado, and
  • Cocoa beans (this is good news, huh!)

Some prebiotics are also common food additives. Look out for foods containing inulin and oligofructose.

And to include more probiotics in your diet, look for these foods:

  • Dairy or non-dairy yogurt (without added sugar or artificial sweeteners)
  • Condiments such as kimchi, pickles, and sauerkraut

The foods we have listed so far make for great parts of a healthy diet. If you would prefer a more targeted approach however, you can always take pre- and probiotics as supplements. And this is certainly worth considering because some strains of probiotics cannot be obtained through food. 

Probiology Probiotics

Frequently Asked Questions

Do prebiotics help you lose weight?

Taking prebiotics can have a significant impact on your weight loss. This is particularly the case when your excess weight is caused (at least in part) by dysbiosis.

Dysbiosis is a condition in which there’s an imbalance between the good and bad bacteria in your gut.

This condition directly contributes to excess body weight, by suppressing the hormones that tell your brain when you are full and that maintain stable blood sugar levels. 

Prebiotics can help you lose weight in several ways.

They help you to feel fuller sooner, they reduce the amount of fat absorbed from your food, they produce SCFAs to suppress appetite and help good bacteria thrive, they work synergistically with gut bacteria and probiotics, and some prebiotics also support good anaerobic bacteria.

How Often Should You Take Prebiotics?

There are some experts who say that you should consume at least 5 grams of prebiotics in your diet every day.

However, we would strongly recommend that you build up to this level gradually, starting with small amounts, so that your gut can grow accustomed to having them.

Written and Medically Reviewed By

  • Chelsea Cleary, RDN

    Chelsea is a Registered Dietitian Nutritionist (RDN) specializing in holistic treatment for chronic digestive disorders such as Irritable Bowel Syndrome (IBS), SIBO, and Crohn’s disease. She educates patients on how they can heal themselves from their conditions by modifying lifestyle and dietary habits.

  • Julie Guider, M.D.

    Dr. Julie Guider earned her medical degree from Louisiana State University School of Medicine. She completed residency in internal medicine at the University of Virginia. She completed her general gastroenterology and advanced endoscopy fellowships at University of Texas-Houston. She is a member of several national GI societies including the AGA, ACG, and ASGE as well as state and local medical societies.