Just looked it up and I'm mistaken about being solely responsible for 'gut feelings' more of a cross and interaction of nervous systems.https://en.m.wikipedia.org/wiki/Enteric_nervous_system
So the digestive system neurons are roughly the total amount in 2/3rds of a cat.
Not even including the microbial biome interaction. Some of the bacteria and stuff also produce enzymes and neurotransmitters and aid in the breakdown of food.https://www.ket.org/health/intestinal-biome-gut-together/
Also the microbial gene expression and population changes very fast.https://www.scientificamerican.com/article/the-guts-microbiome-changes-diet/
It looks like proper gut biome at the start (vaginal seeding and breast feeding) (not destroying it all with anti-bacterial medication) reduces the chance of obesity, and allergies.
Just from a quick search, but it looks like most researchers onky have a rough idea on what is going on with specific strains of bacteria.
The best guess is maximize different foods and eat fermented foods.
>In before eating pussy and ass a day cures obesity and allergies. (Fecal transplants Do work though.) https://en.m.wikipedia.org/wiki/Fecal_bacteriotherapy
(People also can do it themselves apparently…)(Saline solution and poo in a reverse enema)