Adenosine triphosphate (ATP) is a molecule used to transfer chemical energy inside cells: a series of chemical reactions called the citric acid cycle (or Krebs cycle) allows the mitochondria in our cells to convert carbohydrates (i.e. glucose), fats and proteins into carbon dioxide (waste) and ATP, which is used for cell function.

There is some evidence that a ketogenic diet is beneficial to the production of ATP by mitochondria within the brain.