During periods of fasting, fatty acids released from the adipose tissues are oxidized in the liver, skeletal muscle, and cardiac muscle for energy production. The brain does not directly utilize fatty acids, but oxidizes ketone bodies derived from β-oxidation of fatty acids in the liver. When fatty acid oxidation is defective, fats released from the adipose tissue cannot be oxidized, and accumulate in organs such as the skeletal and cardiac muscles, impairing their function. Moreover, the liver is unable to produce ketones bodies resulting in energy deficiency.