Abstract The activities of alanine transaminase, adenylate deaminase, glutamine synthetase and serine dehydratase were studied in liver and muscle of rat pups exposed to a cafeteria diet and glutamine gavage. Plasma was used for the determination of proteins, glucose, lactate, acetoacetate, 3-hydroxybutyrate, amino acids, and urea. Circulating ketone bodies are lower in glutamine gavaged pups in the two diets used. Glutamine gavage enhances liver adenylate deaminase and inhibits serine dehydratase and glutamine synthetase in chow fed pups. From the results, a minor incidence of glutamine gavage in pups fed on cafeteria diet is postulated.