Seems true. Before I started listening to my doctor and health coach I tried to limit my intake to my calorie burn. What tosses a wrench into the formula, as it was explained to me, is individual metabolism. Hence the earlier statement about 20 something athletes with high carbohydrate preloading before cycling, running or swimming. Yes they may be setting themselves up for problems later in life but when their body is burning energy like a blast furnace they can get away with it. Then one day, if they are like me, the furnace seems to slow down and the intake must decrease because the outgoing simply isn't happening like it used to. This is why we have added zone training to me. It seems true that even during Anaerobic efforts you do burn fat. But you also allow your body to look for quick energy and that is found in the muscle itself. So in zone 3 in my case aerobic I can burn fat and keep my muscle structure while losing weight. A health coach does more than help you lose weight they help you do it properly based on the tests made on your body. Therefore what works for me might be 180 out from what the suggest for someone else. For me 2000 calories in and 2000 calories out didn't work. But for someone else it might be fine, for me it meant plateau.