But once they diet to a point where they are not obese, the bacteria dies off? I believe the theory is the reverse - by killing off the bacteria, the person be

But once they diet to a point where they are not obese, the bacteria dies off? I believe the theory is the reverse - by killing off the bacteria, the person becomes less obese. Anti-biotics probably won't work as well as you hope because they kill all the bacteria in the gut - good and bad - which will just create more digestive problems.