There is a company testing part of this hypothesis; at least the oral antibiotics. Giving oral vancomycin followed by placebo or specific probiotics to people with obesity. Their probiotics have been shown to increase GLP-1 which generally is associated with decreased cravings. See https://pendulumlife.com/pages/research-clinical-trials
Discussion
Oral vanc is an interesting choice. Won’t be absorbed, which is good, but kinda kills like everything, right? Last I used it was like a decade ago as an intern to treat C. Diff.
I hope they get to the bottom of this, whether the hypothesis is true or not. Our future as a nation depends on at least some of us being capable and proficient at apply physical force and violence, which is hard to do if we all grow fat and lazy.
Kills all gram positives but many organisms in our gut are gram negative. I'm convinced there isn't one fix for this. I'm convinced microbiome is part of it. Interestingly enough, I've seen more than one person lose substantial weight after taking metronidazole for some parasitic infection. And feel way better so I don't think it was the parasite sucking the life out of the person afterward.