I've always believed that will power is a mug's game.
Believing that will power is all you need sets you up to fail, because when you give in to a craving, you feel guilty about not being "strong" enough to withstand it, which leads to more emotional eating for a lot of us.
Like WFEN, I am a bit believer in exercise. It just makes me feel so much better, regardless of weight.
What I do is to try to just build all of my health goals into my daily routine, so that I don't even have to think about it. If it's automatic, then it just happens.
For example: If there is chocolate in the house, I will eat it. I'm talking pounds and pounds of it. So...I don't keep it in the house. If I go for a few months without chocolate, then I lose the taste for it and can keep that craving switched off. But...if I have even one bite, then I start to want it all the time. I think about it, obsess even. (Golly...just writing this makes me realize that my "chocolate jones" has all the earmarks of a true addiction. Never realized that before.)
With exercise, I can't get to the gym for love or money, so I try to force exercise on myself in other ways. The subway stop nearest to my office is about a 15-minute walk, so instead of taking the bus connection, I walk the rest of the way. And in Toronto, a lot of the downtown office buildings are connected to each other through the PATH (a series of underground tunnels, with shops, restaurants, a post office, etc.) so when it's nasty-cold outside, I can get all my errands done, walk about a mile, and not use the bad weather as an excuse.
If it's just "stuff I have to do" then it's not part of a diet, and it seems far less daunting to me, somehow.
Incidentally, I play the same trick on myself with the alarm clock. I set the clock 20 minutes early. Although I know perfectly well that the clock is fast, I don't resent getting up that early, because the clock says it's later.
Because I don't call it "exercise", but rather "going to the office", or "buying stamps" or "window shopping", it doesn't intimidate me so much, and I manage to maintain a reasonable fitness level.