Did you realize (I didn't - guess I just hadn't thought about it) that you burn most of your total calories for the day while sleeping and sitting around? I guess if we think about it that makes sense. That hour at the gym that might have burned 300 - 600 calories is about 1/4 of the total calories we burn in a day. In my earlier post about The Fallacies of Fat this author made that point and it does make sense.
I tend to focus on the time I spent in my step aerobics class or body sculpt. I do realize that the 300 calories I used while working out is not the net calories burned because I would have been burning calories anyway sitting at my sewing machine for example rather than in my aerobics class.
I also think this is why people misjudge what calorie benefits that come from exercising. On another note, some food plans allow activity points or give what has to be done to make up for an ice cream cone for example. That is just playing games I think. I know I have eaten something I shouldn't and then did the math for what I would have to do to burn those calories I just ate. Do we really have enough time or stamina to make up for eating a whole pizza? Doubt it.