why can’t you build muscle at a caloric deficit, if you have fat reserves available?

Question

This seems counterintuitive. I mean, if my bills exceed my income, *but* I have a million dollars in the bank, I can still buy new stuff.

I can spend the energy from fat reserves on any amount of exercise, after all – so why can’t I spend it on building muscle? Why does *that* energy have to come from a caloric surplus?

In: 3

Answer 1

It isn’t just calories taken in in that creates muscle mass, it’s calories consumed in specific forms. Fat cannot be converted into muscle because muscle is made from different materials. To stick with your analogy, protein is needed to create muscle mass and fat is like a foreign currency that doesn’t have an exchange rate for protein.