For the most part, as an adult, your microviome has a fixed composition - what you eat will rapidly alter the relative proportions of your gut microbes, but eve

For the most part, as an adult, your microviome has a fixed composition - what you eat will rapidly alter the relative proportions of your gut microbes, but even drastic dietary shifts are unlikely to either kill strains off, or introduce new ones, so any diet will only have so much of an effect, and it'll bounce right back if you go back to your old diet.