evilweasel posted:

I mean it's technically correct in the sense that (a) you can turn fat into muscle without a corresponding weight loss and (b) that when you start exercising your appetite goes up so you tend to eat more to counteract the increased calorie burn.

But it's part of the basic thermodynamic equation of calories taken in vs. calories burned. It works, but there are those two issues in real-world applications of "just run some more". But the phrasing of "it doesn't work" is just rephrasing a more complicated response in a way to justify doing nothing.