Athletes are a great example of what proper exercise and nutrition does for the body. They are living proof, otherwise if it didn't work they'd be all overweight. Now we don't necessarily expect ourselves to be at that level but clearly doing the basics will work wonders or move you in the right direction. I don't think we can nullify the impacts of lots of exercise and world class nutrition because of some eating disorders.
I'd say obesity is the greater eating disorder, not athletes being at the top of the game working themselves into the ground.
But a good thing you point out there, is that it is easy to say exercise consistently and eat a good diet. But the trouble is the discipline/self control to do so.
Many of us lead stressful busy lives which don't always leave us the room to be the healthy people we want to be. You just need to make time for it in a way that you can and enjoy, if you truly do want to prioritise it.