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

Just like how a candle burns slower than paper, or how its easier to drink water rather than milk, Different substances have different attributes. A proper chemist might know more, but it kinda makes sense that you could isolate some excesses of a substance that could, in excess, cause problems.

(Calories are a general rule of thumb but any nutritionist knows its more a concern of excessiveness/lack of moderation which causes health problems like weight gain or other more holistic problems like lack of exercise or depression/poor support structure)