Ketones

Ketones are formed from the breakdown of fatty acids to acetyl groups and are burned throughout the body. Ketones are formed when the body starts to use fat as fuel because of a lack of carbohydrates in the diet. The body preferentially uses glucose as an energy source, and ketones are used for fuel in the absence of glucose. Excess ketones will slowly decarboxylate into acetone which is excreted in the breath and urine.