True, I'm sure some others could gain something useful, but a health forum would probably be a better place for all the details. I think there's a small LessWrong walk away message though, so I'll elaborate a bit here.

I began having various symptoms about 5 years ago. The main things were heart issues (tachycardia, brachycardia, arrhythmias), digestive issues, low body temperature, and cognitive issues (confusion, reduced reflexes, poor multitasking). I was a typical junk food-eating,over caffeinated college student at the onset.

After about a year of worsening symptoms I sought out medical help. Multiple doctors had nothing to say. The last doc I saw diagnosed me with hypothermia. I slapped my face and decided I could do better on my own, and thus started my food experiments. It took a few years and was more difficult than I would have thought (being skinny I never realized how dependent I was on certain foods) but I finally converged on a diet that has largely eliminated all my symptoms.

Treating food like an experiment, rather than a source of pleasure or a chore, has been a great way to exercise rationality and will power. Nutrition is a complicated subject, confounded by conflicting information and individual differences. In addition there are numerous motivations for rationalizations (social pressure, convenience, cravings), and often little confidence about rational conclusions. Combine all that with a need to make level headed hypotheses and the ability to carry out the month long experiments and you have yourself a tricky exercise.