I advise all my friends to do a "one food and work up" diet. I had massive problems with sleep, my skin, my bowel movements, general fatigue, long-onset DOMS after working out - the list goes on. These are completely gone now I pin-pointed the issue. I cut back everything, and added things one ingredient at a time. I started with only root veg, then added legumes, then brassicaceae veg (kale, cauliflower, broccoli etc.) That covered all my nutritional needs bar B12, which I supplement. From there, I've slowly added one more food every couple of week.
My only guess is that I have a histamine response to some kind of compound found in grains and certain types of spices. The body is a strange machination. Honestly, doing the reduction diet was the best thing I've ever done. If you could make a medication that brought me from how I felt 3 years ago to where I am now, you'd be worth more than Bezos.