If it isn't too personal, what have you learned? I'm curious if is common knowledge nutritional stuff that tracking just gave you the willpower to follow (refined carbs are bad!) or something more novel (bacon is the answer!)?
I've discovered some food allergies (soy, bananas, oranges) which have greatly eased symptoms after removal (especially digestion problems).
Magnesium and calcium have strong influences on cardiac events (skipped beats, bounding pulse, etc), but I haven't been able to leverage them to eliminate symptoms completely.
Ginkgo is great for circulation and body warmth (probably specific to my own body chemistry though, as it sounds like most people don't have any reaction to it). Ashwaganda is ridiculous (for me).
I wouldn't be surprised if nothing I've learned applied to anyone else. I don't encourage anyone to follow my specific diet (except for avoiding refined foods), but I do encourage people to track themselves. It's quite empowering.