How does burning calories for energy work? If someone runs on an empty stomach and burns 1500 calories, where did that energy come from? When they eventually eat something, how does the body know what to do with those calories?

Question

How does burning calories for energy work? If someone runs on an empty stomach and burns 1500 calories, where did that energy come from? When they eventually eat something, how does the body know what to do with those calories?

In: Biology

Answer 1

Calories are stored in the body as sugar. Excess sugar gets stored in muscles and body fat, and when starving, the body starts burning fat, then muscles