A.M.
All these "cleanse" protocols are scientifically hocus pocus and yes we all have bacteria that is good for us and messing with it can make you much more susceptible to opportunistic infection. Losing weight is relatively straightforward - eat less but eat a well balanced diet with plenty of fiber and a multivitamin. The fad diets all aim at the same thing, how to get you to eat less. Some of the GI diets are designed to help you avoid the sugar high/low that makes you hungry. But at the end of the day, weightloss is related to total calorie intake compared to total calorie use - no amount of "cleansing" changes that. But it does sell product. Good luck.