An intermediate compound common to both fatty acid and carbohydrate oxidation is
During oxidation of carbohydrates, acetyl CoA is an intermediate compound, produced as a result of decarboxylation of pyruvic acid. Pyruvic acid is the end product of glycolysis. Fatty acids enter the oxidation cycle after it is broken down into acetyl CoA. Even amino acids are converted into pyruvate first and then into acetyl CoA before entering the oxidation cycle. So, acetyl CoA is the common intermediate to fatty acid, carbohydrates and amino acids.