In recent years, scientists have also found that certain bugs in the gut, which contribute to digestion and immune function, are linked with overweight and obesity.(Even more astounding: animal studies found that transplanting feces from obese mice into normal weight mice made them heavier. The opposite was also true.) In humans studies, researchers have found that more diverse communities of bacteria are linked to having a normal weight, while fewer types of bugs were connected to overweight and obesity, though those results were a little uneven.
Excerpted from time.com