Gut Health and Weight Management

So, it turns out our large intestine is full of more than just guts! Deep in our large intestine lives a community of trillions of tiny microbes which make up our gut “microbiota” or “flora”. While this microbial colony in our gut may be difficult to imagine, its effects on health are noteworthy.  

The gut flora is responsible for producing several essential vitamins and minerals, pre-digesting food and breaking down fiber. It is closely linked to health, with research showing that nurturing a healthy gut can decrease your risk of cardiovascular disease, cancers, and autoimmune conditions while improving overall mood and wellbeing. 

More recently, studies have linked the gut to weight management. From preventing weight gain, to causing weight loss, keep reading to learn more about how your gut may be influencing your weight.


Relation to weight

The first ties between the gut microbiota and weight were discovered from research in mice. These studies revealed that germ-free mice (with no gut flora) were leaner than mice that were raised conventionally with a typical gut microbiome. Therefore, indicating that the gut microbiota may affect weight. Another study showed that transplanting the gut microbes of obese mice into lean mice would cause them to gain fat. This research led to the eventual discovery that obese individuals tend to have a much different composition of gut microbes than their lean counterparts.

There are a few patterns in gut microbes that seem linked to weight:

  • The proportion of beneficial microbes to pathogenic microbes. A greater ratio of beneficial to pathogenic bacteria is linked to better weight management.
  • Microbial diversity (the number of individual microbes from different species). Greater microbial diversity is linked to preventing weight gain long-term.
  • Microbial richness (the total number of microbial species). Decreased microbial richness is linked to weight gain. 

It is obvious that the quality, richness and diversity of microbes living in the gut seem to have an important effect on a person’s ability to maintain, gain, or lose weight. These may be due to the guts influence on energy metabolism. Gut microbes play a key role in the metabolism of carbohydrates, essential amino acids and fats. Therefore researchers predict that certain microbial communities affect energy metabolism differently, and therefore affect our weight differently. 


So, how can we change our gut microbiota?

Lucky for us, we are able to change our gut health fairly easily and quickly! Some of the best ways to target our gut health are through the use of probiotics, prebiotics and making some simple changes to our diet. 


Probiotics are living cultures containing billions of microbes in a single dose. They’re typically taken in a supplement (pill) form or are found in certain foods. Probiotics affect our gut health by essentially delivering live beneficial microbes to our gut, in the hopes that they colonize. 

Studies looking at the gut and weight have found that probiotics may reduce body mass index and total body fat. A 2015 study found that probiotic supplements prevented weight gain and body fat increases in a population of 20 healthy men who consumed a high fat diet for a month. These results are not uncommon. In fact, adults who take probiotics tend to have reductions in body weight, BMI and fat mass percentage compared to adults who don’t. 

To get the best results from probiotics, it is important to get them in daily. Also getting probiotics from foods seems to be best because it’s not just about the microbes, but also how they interact with the foods they’re found in. Probiotics are often found in foods like yogurt, cheese, milk, fermented foods (such as kimchi, miso, kombucha and apple cider vinegar), unfiltered juices, and many others. 

Probiotics can also be taken in supplement form.Some of the best strains of probiotic supplements for weight management are Lactobacillus rhamnosusLactobacillus gasseri, and Bifidobacterium lactis.


Prebiotics are a type of fiber that help fuel the gut. Our bodies cannot break down fiber during digestion, and so they reach the gut intact. The gut then breaks down these fibers into usable nutrients, minerals and fuel for the body. 

The best prebiotics are highly fermentable and produce short chain fatty acids (SCFAs). These SCFAs help to fuel the body, are a key energy source for beneficial microbes, and create an acidic environment in the gut. These conditions inhibit the growth of pathogenic bacteria while providing an optimal environment for beneficial bacteria in the gut. Prebiotics are also notorious for improving microbial diversity in the gut. As we mentioned earlier, both of these changes are key for improving weight management! 

Some of the best prebiotics are found in several plant-based foods, such as leeks, asparagus, Jerusalem artichoke, garlic, onion, banana, oats, legumes and seeds. A great product to get your fill of prebiotic fiber are Holy Crap cereals, packed with chia seeds, hemp hearts, oats and buckwheat. 

To get a strong prebiotic effect through food, it is best to eat a variety of prebiotic rich foods every day. Otherwise, supplementation with prebiotics may be a better option.


Diet is another key contributor to our gut microbiota. The overall composition of our gut flora is strongly affected by our diet. 

The western diet, characterized by high protein, high fat and low carbohydrate intake, and the ketogenic diet, characterized by high-fat and low carbohydrate intake, are linked to decreased microbial diversity and quality. These diets tend to increase the number of pathogenic bacteria in our gut and decrease the number of beneficial microbes. Over time, this can lead to dysbiosis, a gut condition that is associated with a number of different diseases.

Mediterranean diets, vegetarian diets and high fiber diets are often considered to be the healthiest diet – and for a good reason. They are associated with good gut health and also tend to prevent weight gain. Many researchers guess that many benefits of these diets are attributed to eating a high proportion of carbohydrates, coming largely from fruits and vegetables, which are rich in fiber (and prebiotics!). 


So, basically what we're saying is...

Research has identified a clear link between gut microbes and weight management. All of us house a unique community of microbes in our gut. Luckily we have a pretty good level of control over its composition and diversity. Some of the best ways to affect real change in our gut is through probiotics, prebiotics and diet. 

Eating a plant-based, carbohydrate-rich diet high in prebiotic fiber and probiotic foods seems to be the gold standard for enhancing your gut microbes. By doing so, you can increase the proportions, richness and diversity of beneficial bacteria and reap all of the benefits that come with them – like better energy metabolism and weight management!

The microbes in your gut might be the only bugs you’ll ever try to help live in your body. But in doing so, you can reap the many benefits that a healthy microbiota can bring, which we’ve established are plentiful!



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