The chemical reactions and pathways resulting in the breakdown of ketone bodies, any one of the three substances: acetoacetate, D-3-hydroxybutyrate (beta-hydroxybutyrate) or acetone. Ketone bodies can be used as an energy source as an alternative to glucose. Utilization of ketone bodies in peripheral tissues involves conversion of acetoacetate to acetoacetyl-CoA, which is then converted to two molecules of acetyl-CoA.