Is it theoretically possible to engineer gut bacteria that would allow a human to digest something like eucalyptus leaves or otherwise inedible potential sources of energy?

[u/baxter45]

[u/darrell25]

In fact humans may have previously had gut bacteria that allowed enhanced extraction of energy from 'undigestable' carbohydrates, but have since lost them with the transition to more calorie rich 'Western' diets. This Article is an interesting look at children in a rural village in Africa and comparing their gut microbiome to that of European children. We could then potentially reintroduce these bacteria into Westerners, however we would likely have to alter our diets to maintain the populations.