"Let food be thy medicine and let thy medicine be thy food" Hippocrates
The idea of food as medicine has been around since ancient times, its funny how today we've completely disassociated the idea that food makes you feel good or bad, and that food has a direct impact on our health and how we feel everyday.
Have you considered how foods make you feel - does caffeine perk you up but then make you jittery? When you eat a donut or a big bowl of pasta do you feel good afterwards? How about more subtle things, like when you eat dairy do you experience that your skin breaks out a few days later, or that you wake up the next morning and are more congested than usual? Food directly impacts how we feel and directly impacts our health. Experimenting with how foods impact your body is a great way to determine what you want to eat for your optimal health. Personally I think that whole foods make me feel best, and I've found that I operate and feel much better when I eat clean.