Originally Posted by
DrIsotope
No... that works forever. Because you know, physics. However, as fitness level increases, the amount of energy required to complete a task lessens-- so the intake must be constantly reduced to accommodate. But in the end, so long as output exceeds input, weight loss occurs. And this is coming from a guy that went from 237 to 190. It still works. I eat less now because I need to eat less. After all, I am now 20% smaller.
The issue becomes being unable to continue the high intensity work because you can't recover correctly. I'm doing some VO2max training with a group right now and any calorie deficit that day is destroyed by the fact that I'm absolutely starving the rest of the week, and even with a decent protein intake to help my muscles it takes me almost the entire week to recover or my numbers aren't good enough during the next session.
I made the mistake of going on a not-particularly difficult ride three days after and completely undid the three days of recovery and was off by 20+ watts on the hard intervals after the first, and that defeats the purpose of the training.
Physical laws still work, but you can't function that way for very long. You're fighting nature, but in a different way.
Best weight loss happened with less calories burned in intense exercise, because my body wasn't screaming to replace the (as far as the animal brain is concerned) all important glycogen store.