energy in the form of high-energy molecules, such as adenosine triphosphate (ATP), for use in various cellular processes.

While carbohydrates are essential to human biological processes, consuming them is not essential for humans. There are healthy human populations that do not consume carbohydrates.In humans, carbohydrates are available directly from consumption, from carbohydrate storage, or by conversion from fat components including fatty acids that are either stored or consumed directly.