eli5 how do drinks have zero calories but have ingredients?

Question

eli5 how do drinks have zero calories but have ingredients?

In: 2

Answer 1

because not everything we eat can be metabolized and turned into energy. Your body has no pathways breakdown aspartame into a substance that it can use, so, even though you can put it in a bomb calorometer, burn it and get a reading from it, it is of zero use to your body.