What process converts food into energy in the body?

Metabolism is the overarching process that converts food into energy in the body. It encompasses a series of biochemical reactions that occur after food is ingested, where macronutrients like carbohydrates, proteins, and fats are broken down into simpler molecules. These molecules are then used to produce adenosine triphosphate (ATP), which is the primary energy currency of the cell.

While digestion is a critical initial step that breaks down food into smaller components, it is metabolism that includes both the breakdown (catabolism) and the buildup (anabolism) of these components to release and utilize energy. Absorption follows digestion and refers to the uptake of these smaller molecules into the bloodstream from the gastrointestinal tract, but it does not directly involve energy conversion, and fermentation is a specific process that mainly occurs in certain organisms, not generally applicable to human metabolism on the whole. Thus, metabolism truly encompasses the complete process of converting food into usable energy for the body.