Fig. 2
The metabolic inflexibility of type 2 diabetes. Metabolic flexibility is often quantified as the change in non-protein respiratory exchange ratio between metabolic extremes; for example, the fasting state and the metabolic milieu created by supraphysiological insulin stimulation during a hyperinsulinemic euglycemic clamp. In their study, van de Weijer et al. confirmed that subjects with type 2 diabetes demonstrate a higher NPRER (less lipid use) during fasting (open bars) and a lower NPRER (less carbohydrate use) during maximal insulin stimulation (closed bars) [83]. Consequently, these patients demonstrate metabolic inflexibility (reduced ΔNPRERclamp-fast; grey bars) compared to their non-diseased counterparts