Hey Paul,
Try not to beat yourself up. I too struggle with obesity (hate that word) as many of us do. Some are ok with it and you like myself are obviously not. What helps me is to just live day by day. If I happen to eat crap that's not good for me I dont beat myself up mentally, I just go out and kick butt to work it off the next day. That has actually helped me to eat better. I was craving a cookie something fierce yesterday and I could have had it or maybe half and stepped up my game today, but the thought of what it would take to work it off was a huge deterrent. This site has helped me improve my riding making it much more enjoyable, and I've learned (the hard way) what and what not to put in my body before and after riding.
You can do this, we all can...