Hi M3F, I'm new here, but read your post and thought I might also add some ideas for you.
I totally agree with all of the notes about letting yourself know why YOU want this. It's not a willpower thing, it's a want power thing.
(If willpower worked, we wouldn't have a $60 billion a year weight loss industry in the U.S. It's the only business model I know of that makes more money the more people it fails.) But I digress.
Try right before you go to sleep and right as you wake up seeing yourself becoming more and more healthful every day. You'd also be well served by imagining moments where you've been tempted in the past, and how you would make more healthful choices this time.
When I was a kid, I was raised to eat everything on my plate, because cosmically, someone in Africa was dying of starvation if I didn't. Never really got that logic, but I did have big time hangups about leaving food on my plate.
It helped when I started to visualize being calm and sure of myself when I left food on my plate when I was satisfied. Not full, but satisfied.
Finally, continue to get group support, as you can here, and track your progress. I literally give myself a sticker on the calendar when I've met my daily goals. What can I say, gal likes a sticker. I'm visual, and this works for me.
Hope this helps! Warm regards,