When I was young I was obsessed with my image in the mirror so I ate very little and always what was considered healthy for the time. This lead me to being a complete wreck, mentally and emotionally.
Then I moved on to eating for performance. I felt better this way, but again this became an obsession. I was always working on improving my cross-fit numbers and occasionally still trying to look like a magazine cover.
The best thing I ever did was stop following a diet (for mental sanity) for about a year and just try to be reasonable with my diet. "Junk food" some days or weeks and healthy eating more often than not. I gained a decent amount of fat, but I no longer obsessed over my image or performance. I also learned that eating well most of the time kept me in the ball park with looks and my performance didn't suffer at all.
I think there many reasons to eat and I eat for all of them during different seasons of my life.