I am a C5/C6 quad and therefore I am pretty much unable to do any meaningful exercise. My main control is to manage my diet. I know that is not easy, especially since food can be like a drug. I have been on a bad eating habit the first 12 years after my injury, but turned things around by eating more vegetables and pretty much cutting out meat, dairy, and bread. Then, about a year and a half ago I did a 60 day detoxification diet where I lost 25 pounds. This might be a little bit too extreme for you, but I wrote about my experience in my blog.
http://www.disabledandproductive.com/articles/disabled-diet-detoxifying-a-disabled-body-through-juice-feasting/