I read somewhere a long time ago that 100 calories burned=1 AP. Not sure if that's even right anymore, but I keep that in mind. My goal is to burn between 400-600 calories/day. I never use the AP's for more food unless I am doing a 1000+ calorie day (in addition to cycling, I also do a lot of hiking, usually 6-10 mile trips). I need the extra calories then, so I don't feel as bad, but only trade in 4 at the most.