The Effects of Self-Control on Glucose Utilization in a Hyperinsulinemic Euglycemic Glucose Clamp

Abstract. Background. The glucose hypothesis of self-control posits that acts of self-control may draw upon glucose as a source of energy, leading to a decrease in blood glucose levels after exerting self-control, mirroring the temporary depletion of self-control, but supporting evidence is mixed and inconclusive. This might partly be due to using methods that are not suitable to reliably quantify glucose utilization. Aims. We aimed at examining whether self-control exertion leads to an increase in glucose utilization. Method. In a sample of N = 30 healthy participants (50% women, age 26.5 ± 3.5 years) we combined a hyperinsulinemic euglycemic glucose clamp (a well-established and validated procedure in experimental endocrinology to reliably quantify systemic glucose utilization) with a standard self-control dual-task paradigm. In the first task, the experimental group completed a variation of a paper-and-pencil crossing out letter task (COLT) that demanded self-control; the control group completed a variation of the COLT that did not demand self-control. The second task for both groups was a computerized two-color word Stroop which demanded self-control. Results. We did not find a significant main effect for time, nor a time × group interaction with respect to glucose utilization, which indicates that glucose utilization did not differ significantly over time or between groups. Limitations. Due to the time-consuming and complicated clamp method, our sample was rather small. Conclusion. Our results revealed little evidence for the notion that self-control efforts are associated with a relevant increase in peripheral glucose utilization.