What’s in Your Gut Affects How Much You Weigh

gut microbes weight

Why are some people able to eat whatever they want and never get fat?

Science may now have an answer.

We all know someone, who you may even envy, that can eat whatever they want whenever they want and never have to worry about their weight.

Sure some of these individuals only do that for show. The rest of the time they aren’t eating much, plus they regularly exercise.

But then there are those that are naturally ‘gifted’.

As it turns out these individuals who are able to avoid gaining weight have their parents to thank.

Researchers at Cornell University in New York and King’s College in the U.K. revealed that our genetics play a big role in whether we’re fat or thin.

The study found that our genes influence that types of microbes in our gut, making some thrive more than others. And which type of bacteria you have influences the way you gain, or don’t gain extra weight.

For those who have the right microbes, staying thin and slim is much easier.


What’s in Your Gut

The study was published in the November 2015 issue of the journal Cell. The article, titled “Human Genetics Shape the Gut Microbiome”, reveals that a certain type of gut bacteria, called Christensenellaceae, was more abundant in individuals with low body weight compared to those who were overweight or obese.

The presence of this family of bacteria, however, is largely genetic. So you inherit it from your parents when you’re born.


Your Genes Play a Role

To perform the study, the researchers sequenced the genes of microbes in fecal samples taken from 416 sets of twins. They were able to find the twins by using the TwinsUK registry, which contains a large databased of twins in the U.K., and was created to help study age related diseases.

Of the twin pairs in the study, 245 sets were non-identical twins while the remaining 171 were identical.

What the researchers found was that identical twins had similar abundance of certain types of gut bacteria. This makes sense because identical twins share 100% of their genes.

Non-identical twins, who only share 50% of their genes, didn’t show that same similarity. This revealed that your genes do influence the type of bacteria that’s present in our guts.

Those whose gut microbes had a certain strain of bacteria called Christensenellaceae, tended to have lower body weight compared to those who didn’t.

To test whether or not this bacteria actually made the difference, the researchers treated mice with this strain.

The mice that received the bacteria, did in fact gain less weight compared to the mice that didn’t receive it. This led the researchers to conclude that the presence of Christensenellaceae in the gut helps keep weight off and prevent obesity.



The discovery found by the researchers offers valuable insight on why some individuals have more difficulty keeping the weight off or losing weight even when they follow the right diet, exercise and make proper lifestyle changes.

The presence of certain groups of microbes, some of them beneficial to us, helps keep the weight off and prevent obesity. The specific microbe found in the study however, is hereditary so it requires inheriting it from your parents.

The good news is the discovery of this specific bacteria and its function, allows scientists to possibly create new treatments as well as dietary measures to help combat the obesity epidemic.

Finally, it also makes us aware that losing weight isn’t just based on diet, exercise and lifestyle.