"Much work has been done in obesity research. Scientists have consistently found that people with a BMI [body mass index] >30 have different gut microbes than people with BMIs in the "normal" range. As well, bariatric surgery also significantly changes gut microbes as people lose weight, making them look more similar to the bacterial profiles seen in "normal weight" individuals. A more recent study in The ISME Journal proposed a microbiome diet: eating foods that would eliminate a type of bacteria called Enterobacter helped a person lose drastic amounts of weight in a short period of time (Fei & Zhao, 2012)."
Gut feelings: EDs and the microbiome - ED Bites