> While unhappy microbiomes can be unhappy in their own way, we do not have a consensus on what a “healthy” gut microbiome looks like, either. In collaboration with a continent-wide consortium in Africa, our lab helped catalogue the species found in healthy adult women across the continent. We found over 1,000 new species relative to what had been previously described in studies focused on Western countries.

>Companies trying to introduce targeted combinations of microbes into the gut are thus forever shooting at a moving target.

IIRC, the only semi-reliable way to "adjust" one's microbiome is to find someone who is healthy (and preferably your target body composition/energy levels/psychological profile; and, even more preferably - and possibly paradoxically - who is as close to "you", genetically and physiologically, as possible), harvest and freeze their feces, and take a daily, months-long course of the resulting poop pills, hoping that their gut microbes colonize your own digestive system.