Figure out which bacteria the obese patients have in common that the thin ones don't, and figure out a way to eliminate it.
Sounds easy, but there are more bacterial cells in your body than eukaryotic (human) cells by a factor of 10, and unlike the human cells that all have the same DNA, the bacteria are different. By the way, if you want to know what various types of bacteria are in your personal stool, you can go to American Gut and pay someone $99 to analyze your shit. The answer, however, will be fairly general, because no one's sequenced all the different bacteria there.
Can you name a single primarily psychopathic society to provide even anecdotal experimental evidence for your claim? Theory is nice and all, but is notoriously inapplicable to human behavior.
Lord of the Flies.
Variables don't; constants aren't.