There is great deal of evidence to show that our guts used to be in a much healthier state decades ago. For example, the Hadza in Africa, one of the last ‘hunter-gatherer’ species on the planet, appear to have 300% more bacteria in their guts than we do. It seems that over time we have lost many of these bacteria, and whatever functions they once provided. In terms of gut health, one metric that’s often used is diversity. Similar to the environment, it’s often thought that the health of any ecosystem is related to the number of species in it and their relative abundance. Harmony is basically ...