Inability to lose weight

I had 3 stents put in 4 years ago. At that time I quit smoking and started taking Plavix, diovan, toprol, simvastatin, and a low-dose aspirin. I also started gaining 5 pounds per month. In the meantime, I have tried Weight Watchers, South Beach, and calorie counting. I have had an extensive endocrinology work up that shows nothing is wrong. I recently bought a bodybugg so that I could track calorie burn more accurately. I go to the gym for an hour every day and I work really hard. My activity and food logs show that I am burning about 800 calories more than I take in, on average. Yet I'm still not losing any weight. The bodybugg people tell me that it is obvious that I'm not recording my food properly. I know that I am. It just seems to be a whole lot of work and the only result is that at least I'm not gaining anymore. I had to have another stent put in last summer. I am convinced that I will continue to be at risk for a heart attack unless I can lose the extra weight. I'm a bit stressed and fearful that Nutrisystems won't work either and then I'm out of options. Does anyone have any idea what's causing this and how to get past it?