While I won't disagree that mindset is very important and mental health and physical health are connected (I know, I've had intestinal problems for a while now that are very much stress-related), I don't think you can write off the fact that being grossly overweight just isn't good for your body.

Instead of being fat and loving it or being fat and hating it, why not eat the pie and then go out and bike 10k, seriously. :/ Exercise will always make you feel good in the short and long run. Mistreating your body will fuck you up eventually....