Your gut bacteria may influence how much food your body absorbs
Even if we many times press the importance of understanding caloric balance, one must be humble to the fact that caloric balance is influenced by many other factors than just how much we eat and how much we move. We have already talked about how the body changes BMR, TEA, and SPA to counteract caloric imbalance, but another area of research worth mentioning is the impact of the bacteria living in our gut, called the gut flora.
There are more bacteria in your gut than there are cells in your entire body, and new research is shedding light on how much more important these bacteria are for our well-being than previously thought, with POTENTIAL (i.e. not yet proven) links to depression, inflammatory diseases and obesity.
Certain types of bacteria have been seen more commonly in overweight people compared to leaner individuals. This, however, is just a correlation and does not necessarily mean that the bacteria CAUSE weight gain/loss. It could, for example, be that the obese individuals eat certain food types which cause the gut flora to change since we know that our diets affect our gut flora.
Genes play a central role
Our genes also play a vital role in deciding how friendly our guts are for certain types of bacteria. Interestingly though, one bacterial family, called Christensenellaceae, was more abundant in lean individuals and was “transplanted” into the gut flora of mice. The mice who got the Christensenellaceae-transplant gained less weight than the mice who didn’t get Christensenellaceae!
Whether this applies to humans remains to be seen. Other studies have found that the presence of certain bacteria also influences how much fat we absorb from foods, meaning that people who have a hard time gaining weight may have more of these bacteria in their flora. This branch of research is very new and a lot more studies need to be done before certain conclusions can be drawn, but exciting stuff right?!
Goodrich JK. Human genetics shape the gut microbiome. Cell. 2014 Nov 6;159(4):789-99.
Bäckhed F. The Gut Microbiota as an Environmental Factor That Regulates Fat Storage. Proc. Natl. Acad. Sci. U. S. A., 2004.