– if carbohydrates are the body’s energy source, what exactly are calories?

Question

I keep hearing that carbs are the body’s fuel, but fats contain more calories per gram. Surely that means fat is the body’s primary source of fuel?

In: 3

Answer 1

The body is mostly dual fuel – most of the body tissues can burn either fatty acids or glucose. The fuel use is mostly controlled by the diet; if you eat a high carb diet, most of your energy will come from carbs; if you eat a high fat diet, most of your energy will come from fat.

Protein can also be used for fuel but protein is used by the body for other purposes, which is true for fat as well.