Why is it the calorie count of food, and not the mass, that determines weight gain?

Question

Why is it the calorie count of food, and not the mass, that determines weight gain?

In: 2

Answer 1

Calories mean energy, but whatever energy your body doesn’t use it stores in the form of fat and weight. So eating a lot of calories could mean too much energy your body doesn’t need, which it will convert to fat..

This is why pro athletes eat a lot of calories so that they can do what they need to do as athletes