Your gut (actually, your whole damn body) is home to thousands of species of bacteria, all of which can affect your health. However, it turns out not everyone’s bacteria is created equal. According to new findings published in Science, bacteria transplanted from obese people into mice caused the mice to get fatter, but bacteria from thin people kept the mice thin.
Researchers in Missouri found sets of twins, one obese, one thin, and took samples of their gut bacteria. They then put the bacteria in mice who were raised in a germ-free environment. Mice colonized with the obese twin’s bacteria gained weight, whereas the other mice did not—and the amount of food the mice ate wasn’t the deciding factor. Both sets of mice ate low-fat, high-fibre diets.
Rather, mice with the thin twin’s gut bacteria were better at breaking down fibre into short-chain fatty acids, increasing the amount of energy being burned.
That said, he procedure probably won’t be adapted for humans anytime soon—faecal bacteriotherapy tends to only be used for severe infections. The next step in research will be to figure out the specific roles of specific bacteria, which may eventually help obese people—but not without proper diet. When the mice went to a high-fat, low-fibre diet, both sets got fat.