Question

Why do we calculate calories per gram instead of just calories?

Answer 1

We calculate calories per gram instead because the amout of a certain substance emits a limited amount of heat.✅

Answer 2

Because an amount of the said substance emits a specific amount of heat.

In food usually calories are measured per 100 grams.

For biomolecules calories are measured per 1g (e.g. 1g glucose=4.1kcal)