Long and tedious story short, when I cut milk, gluten/short carbs/whatever pesticide they use for wheat, and excess sugar from e.g. prefabbed food from my diet I gained 10kg and my life basically turned around. Turns out having your gut constantly inflamed is bad for your mental health.
I have missed so many opportunities because of this. It's not right.
ED: Apparently I need to point out that one possible cause may be that antibiotics killed the gut bacteria I needed to process milk, wheat and sugar. If so, this malady could be solved with a less revolting alternative to fecal transplants.