Nutrients can regulate, directly or indirectly, the pathway of expression of genes coding for enzymes involved in metabolic pathways related to the utilization of carbohydrates, lipids and amino acids. On the other hand, nutrients such as carbohydrates, lipids or amino acids can generate an specific hormonal state in the organism, and hormones are the mediators throughout which some genes are activated. The objective of the present review is to show some specific examples of dietary and hormonal regulation of enzyme genes involved in the metabolism of carbohydrates (phosphoenol pyruvate carboxykinase), lipids (malic enzyme) and amino acids (serine dehydratase).