system
Given the following post, respond as if you're commenting on Reddit:
human
How come we get no energy from water? Calorie-wise that is.
gpt
I can answer longer if this isn't what you're looking for.

Take carbohydrates for example, there is a lot of energy stored in the carbon-carbon and carbon-hydrogen bonds. Our cells break these bonds and reform them with oxygen we breath to form CO2 and H2O molecules which are at a lower energy state.

H2O in water is already at a very low energy state and our body has no process by which to breakup H2O into even lower energy components and get calories from it.