The role of amino acid oxidation in causing ‘specific dynamic action’ in man

The increase in metabolic rate which occurs after ingestion of protein (the so-called ‘specific dynamic action’) has been attributed to the energy requirements for urea synthesis and amino acid degradation. 2. We have tested, in normal adult subjects, the effect of meals which increase or decrease the rate of urea production, and our results do not substantiate this hypothesis. 3. The difficulties of accurate measurement of resting metabolic rate are discussed. 4. The term ‘specific dynamic action’ is inappropriate since the effect is not specific. We believe that it may prove to be a reflection of protein synthesis rather than of protein catabolism.