The nutritional sensitivity of the diurnal cycling of body protein enables protein deposition to be measured in subjects at nitrogen equilibrium.

In adults in overall protein balance on intakes of protein equal to or greater than minimum requirements, the diurnal pattern of feeding and fasting results in cycling of body protein, with fasted losses and fed state gains of increasing amplitude with increasing habitual protein intake. Measurement of the slope of the fed state gain-intake relationship enables investigation of the ability of various patient groups to utilise dietary protein, without the need to impose negative nitrogen balance due to sub-maintenance protein intakes.