# Ketone Bodies --- **Ketone bodies** is the collective name of the three particular [[ketones]] that we can produce in the body: **acetoacetic acid**, **ß-hydroxybutyric acid**, and **acetone**. These ketone bodies are produced in the [[liver]] from extra [[acetyl CoA]] to be used as *alternative fuel* by (some parts of) the [[brain]], some [[kidneys]] cell, and some others if [[glucose]] is not available. When two [[acetyl CoA]] combine, they form a ketone body. They're also used as the primary energy source for the whole body when there is a complete lack of glucose, such as for patients with untreated [[type 1 diabetes mellitus|type 1 diabetes]]. It's not as efficient as [[glucose]], but it's better than starving. Ketones are always being produced, but they are produced at a higher rate during [[fasting state|fasting]], a reduced amount of dietary [[carbohydrates]] or prolonged [[physical activity|exercise]]. **Acetone** is the simplest, but also least abundant ketone body. ![[acetone.png]] ___