If a food is said to have 100kcal do we get all of those?

Question

If a banana is said to have 100kcal and you and I eat it are we going to get:

1. all of those calories?

2. the same amount of energy or it varies person to person?

In: Biology

Answer 1

Well your body is not a 100% efficiency machine (nor anything else in the universe) so losses here/there/everywhere.

Different persons gonna be different efficiencies; think new car engine vs old car engine.