Might be something to this. If you kill off certain types of gut bacteria, you don't have those bacteria helping to break down that much food and it just passes through.
Not saying this is healthy. From what I understand, this is how your guts are supposed to work...
You are not a horse or cow. Humans don’t use bacterial processes to break down food.
Ruminants have special stomachs, and the bacteria generally breakdown cellulose. Humans have a single chamber stomach, and cannot digest cellulose (even fat people).
The bacteria normally found in the gut are very beneficial to many bodily functions including immune response.
Five pounds is not much, it could all be due to water retention or something like that. Your body weight fluctuates by a few pounds just due to variations in your diet, activity, the season, etc. However, the obesity epidemic in America isn’t about people who are five pounds, or ten, or even fifteen pounds overweight. I see, every single day, multiple people who are 30, 40, 50 pounds or more overweight. To think bacteria are the cause of that gross obesity just defies common sense. Why wouldn’t every country on the planet have the same problem if that were true?