Do probiotics make you lose weight?

Having the right number of each of the different types of bacteria and fungi living in your gut has been proven to be essential for a healthy metabolism, a strong immune system as well as for mental health.


Probiotics: More than gut health

TL;DR: Gut microbiome has a significant role to play in our health. When you start eating a healthier diet, so do your friendly little bugs living inside you. You will be rewarded with a stronger immune system, more efficient metabolism and weight loss. 

100 Trillion. That is the number of microorganisms living in the human digestive tract1. Some are good for your wellbeing and others cause disease, but they all live together inside you. This colony of microbes is called your gut microbiome. Probiotics are a combination of live beneficial bacteria and/or yeasts that naturally live in your body.

In recent years it has been recognised that the gut microbiome has a significant role to play in our health, extending to all parts of the human body2. They have an impact on much more than just the colon.

Having the right number of each of the different types of bacteria and fungi living in your gut has been proven to be essential for a healthy metabolism, a strong immune system as well as for mental health. In fact when the balance is disrupted we start to suffer with problems such as irritable bowel syndrome (IBS), fatigue, sugar cravings, unexplained weight gain, skin irritations, allergies, autoimmune conditions, headaches and depression and anxiety3.


How does the gut microbiome affect weight?

When researchers have studied the different strains of bacteria found in the gut, they have found a distinct difference between those found in the gut of obese people compared to those found in normal weight people.

Overweight people have fewer different types of bacteria in their digestive tract4. It may sound like a good thing, but while you definitely don’t want a lot of fat cells in your body, you want a greater variety when it comes to bacteria.

Some of the bacteria that thrive in obese individuals are the ones that can digest the parts of foods we can’t digest for ourselves. They are able to extract more energy out of the food we eat than the bacteria found in people who don’t struggle with their weight5. This is one explanation for unexplained weight gain and difficulty losing weight.

Another problem associated with dysbiosis is enhanced fat storage6. Definitely not something you need when you are trying to lose weight! To make matters worse, some of the by-products of the digestion of certain food components by bacteria prevent the breakdown of fat and promote the formation of new fat cells.

Gut microbes also have an impact on the hormones that control our appetite7. The most significant one is called glucagon-like peptide-1 or GLP-1 for short. It helps to tell us when we have had enough to eat by controlling the release of insulin, slowing down the rate at which the stomach empties and increasing our sense of fullness. An imbalanced gut microbiome can result in a lower concentration of this hormone. So it becomes difficult to sense when you have had enough to eat.

Your gut bacteria may even be responsible for your insatiable sugar craving. Certain strains of bacteria feed on sugar. The more sugar you eat, the more they grow and multiply until their numbers are so great that you start craving more and more sugar.


You can change your gut bacteria

It may sound like you have lost the weight loss battle. The little bugs living in your gut seem to have absolute control. Thank goodness this is not true!

Ultimately you are in control of the microbes in your digestive system. It is you that decides what to eat. You don’t have to listen to them. If you provide fuel for the bacteria that promote weight loss and a healthy metabolism, that is what you will see. If you provide fuel for the bad guys, then you will continue to fight a losing battle.

So, what should you eat to improve the balance of microorganisms in your gut?

  • Eat a wide variety of foods. Greater microbe diversity comes from a greater variety of food sources.
  • Eat lots of fruit and vegetables.
  • Include beans, lentils and chickpeas in your diet.
  • Fermented food such as yoghurt, kimchi, sauerkraut and kefir.
  • Avoid refined carbohydrate foods and eat more whole grains.

You will notice that all of the foods listed here, except the fermented foods, contain a lot of fiber. Both roughage and water soluble fiber are important for a healthy bacterial colony. While we cannot digest the fiber in our food, the microbes love it! 

To give your gut microbiome a boost, you could consider taking a probiotic supplement. It is a convenient way to introduce more good bacteria into your digestive tract. Look for one that contains a significant number of viable bacteria. 



  1. Thursby E, Juge N. Introduction to the human gut microbiota. Biochemical Journal. 2017;474(11):1823-1836.
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  3. Hills R, Pontefract B, Mishcon H, Black C, Sutton S, Theberge C. Gut Microbiome: Profound Implications for Diet and Disease. Nutrients. 2019;11(7):1613.
  4. Aoun A, Darwish F, Hamod N. The Influence of the Gut Microbiome on Obesity in Adults and the Role of Probiotics, Prebiotics, and Synbiotics for Weight Loss. Preventive Nutrition and Food Science. 2020;25(2):113-123.
  5. Krajmalnik-Brown R, Ilhan Z, Kang D, DiBaise J. Effects of Gut Microbes on Nutrient Absorption and Energy Regulation. Nutrition in Clinical Practice. 2012;27(2):201-214.
  6. Sun L, Ma L, Ma Y, Zhang F, Zhao C, Nie Y. Insights into the role of gut microbiota in obesity: pathogenesis, mechanisms, and therapeutic perspectives. Protein & Cell. 2018;9(5):397-403
  7. Zhao L, Chen Y, Xia F, Abudukerimu B, Zhang W, Guo Y et al. A Glucagon-Like Peptide-1 Receptor Agonist Lowers Weight by Modulating the Structure of Gut Microbiota. Frontiers in Endocrinology. 2018;9.
  8. Alcock J, Maley C, Aktipis C. Is eating behavior manipulated by the gastrointestinal microbiota? Evolutionary pressures and potential mechanisms. BioEssays. 2014;36(10):940-949.

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