Comment on Smith et al. Protein Ingestion Induces Muscle Insulin Resistance Independent of Leucine-Mediated mTOR Activation. Diabetes 2015;64:1555–1563

Response to Comment on Smith et al. Protein Ingestion Induces Muscle Insulin Resistance Independent of Leucine-Mediated mTOR Activation. Diabetes 2015;64:1555–1563

“…We appreciate Dr. Dioguardi’s critical assessment ( 1 ) of our recently published article ( 2 ). We are a bit perplexed that he considered the outcome from our study predictable.…”

“…Dr. Dioguardi ( 1 ) suggests potential alternative mechanisms that could be responsible for the adverse effects of protein on glucose disposal (i.e., alanine- and arginine-mediated inhibition of glucose disposal) and argues that chronic supplementation with essential amino acids (including leucine) will actually improve insulin sensitivity. Although theoretically possible and to some degree supported by the results from studies of in vitro and animal models, the proposed mechanisms and potential beneficial effect of chronic amino acid supplementation remain speculation until rigorously tested in people, who, as we have shown, are always here to surprise us.…”