Everybody's different so it's more about finding what fits into your life.
For me exercise has to something I want and like to do, my favorite is mountain biking, peddling a bike is not that exiting but peddle it to the top of some fast exiting downhill section of trail then you have a good reason to go to the top of that hill.
Kayaking is also a good one, gives a sense of adventure while getting exercise.
On the food subject all I can do is stay busy, I seems the more I have to do the less I eat.
If you have friends who are into things your into that helps too because then their calling you up and saying stuff like "hey let's go ride this sick trail I just heard about"