Gut flora, good microbes and such. It surely does have a big impact on well-being! I do notice bigger mood swings when my doodies are not swell and solid. :cool: So, optimizing your food intake for good gut flora and such is very important.
I noticed when I had to take antibiotics that all shit hit the fan, so to speak of. Now that I haven't had the need for antibiotics (and I hope that I won't have to take those anymore!) my body is functioning a lot better.
As for coffee, I do drink it black without sweeteners. But nowadays only about 1 cup a day, I notice I react better to matcha or tea for the moment. Yerba mate is pretty good, I just don't have the straw, I have a closing dipper type tea "sifter."