The Effects of Self-Control on Glucose Utilization in a Hyperinsulinemic Euglycemic Glucose Clamp
Abstract
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.
References
2018). Mental work requires physical energy: Self-control is neither exception nor exceptional. Frontiers in Psychology, 9, 1005. https://doi.org/10.3389/fpsyg.2018.01005
(2012). The role of glucose in self-control: Another look at the evidence and an alternative conceptualization. Personality and Social Psychology Review, 16, 143–153. https://doi.org/10.1177/1088868311419817
(2015). How to assess the quality of glucose clamps? Evaluation of clamps performed with Clampart, a novel automated clamp device. Journal of Diabetes Science and Technology, 9, 792–800. https://doi.org/10.1177/1932296815576957
(2015). A series of meta-analytic tests of the depletion effect: Self-control does not seem to rely on a limited resource. Journal of Experimental Psychology. General, 144, 796–815. https://doi.org/10.1037/xge0000083
(2014). Publication bias and the limited strength model of self-control: Has the evidence for ego depletion been overestimated? Frontiers in Psychology, 5, 823. https://doi.org/10.3389/fpsyg.2014.00823
(2016). Testing the role of glucose in self-control: A meta-analysis. Appetite, 107, 222–230. https://doi.org/10.1016/j.appet.2016.07.021
(1981). Synergistic interaction between exercise and insulin on peripheral glucose uptake. Journal of Clinical Investigation, 68, 1468–1474. https://doi.org/10.1172/jci110399
(1979). Glucose clamp technique: A method for quantifying insulin secretion and resistance. American Journal of Physiology, 237, E214–E223. https://doi.org/10.1152/ajpendo.1979.237.3.E214
(2008). Depletion makes the heart grow less helpful: Helping as a function of self-regulatory energy and genetic relatedness. Personality & Social Psychology Bulletin, 34, 1653–1662. https://doi.org/10.1177/0146167208323981
(2009). Moderation of resource depletion in the self-control strength model: Differing effects of two modes of self-control. Personality & Social Psychology Bulletin, 35, 572–583. https://doi.org/10.1177/0146167208330855
(2007). G*Power 3: A flexible statistical power analysis program for the social, behavioral, and biomedical sciences. Behavior Research Methods, 39, 175–191. https://doi.org/10.3758/BF03193146
(2009). Acts of benevolence: A limited-resource account of compliance with charitable requests. Journal of Consumer Research, 35, 906–924. https://doi.org/10.1086/593291
(1987). Insulin action in non-insulin dependent diabetes mellitus: The relationship between hepatic and extrahepatic insulin resistance and obesity. Metabolism, 36, 1091–1095. https://doi.org/10.1016/0026-0495(87)90031-x
(2007). The physiology of willpower: Linking blood glucose to self-control. Personality and Social Psychology Review, 11, 303–327. https://doi.org/10.1177/1088868307303030
(2007). Self-control relies on glucose as a limited energy source: Willpower is more than a metaphor. Journal of Personality and Social Psychology, 92, 325–336. https://doi.org/10.1037/0022-3514.92.2.325
(2010). Modeling the effects of hypoglycemia on a two-choice task in adult humans. Neuropsychology, 24, 652–660. https://doi.org/10.1037/a0020074
(2013). The sweet taste of success: The presence of glucose in the oral cavity moderates the depletion of self-control resources. Personality & Social Psychology Bulletin, 39, 28–42. https://doi.org/10.1177/0146167212459912
(2016). A multilab preregistered replication of the ego-depletion effect. Perspectives on Psychological Science, 11, 546–573. https://doi.org/10.1177/1745691616652873
(1994). Glucose clamps with the Biostator: A critical reappraisal. Hormone and Metabolic Research, 26, 579–583. https://doi.org/10.1055/s-2007-1001763
(2013). Beliefs about willpower determine the impact of glucose on self-control. Proceedings of the National Academy of Sciences of the United States of America, 110, 14837–14842. https://doi.org/10.1073/pnas.1313475110
(2016). Brain insulin resistance at the crossroads of metabolic and cognitive disorders in humans. Physiological Reviews, 96, 1169–1209. https://doi.org/10.1152/physrev.00032.2015
(2010). Does the brain consume additional glucose during self-control tasks? Evolutionary Psychology, 8, 244–259. https://doi.org/10.1177/147470491000800208
(2014, June 7). Calculating confidence intervals for Cohen’s d and eta-squared using SPSS, R, and Stata [Web log post]. Retrieved from http://daniellakens.blogspot.com/2014/06/calculating-confidence-intervals-for.html
(2014). Sweet delusion. Glucose drinks fail to counteract ego depletion. Appetite, 75, 54–63. https://doi.org/10.1016/j.appet.2013.12.020
(2019). New neuroscience of homeostasis and drives for food, water, and salt. New England Journal of Medicine, 380, 459–471. https://doi.org/10.1056/NEJMra1812053
(2004). Glucose improvement of memory: A review. European Journal of Pharmacology, 490, 33–57. https://doi.org/10.1016/j.ejphar.2004.02.043
(2014). Inquisit 4.0 [Computer software].
. (2012). Motivational versus metabolic effects of carbohydrates on self-control. Psychological Science, 23, 1137–1144. https://doi.org/10.1177/0956797612439069
(2000). Self-regulation and depletion of limited resources: Does self-control resemble a muscle? Psychological Bulletin, 126, 247–259. https://doi.org/10.1037/0033-2909.126.2.247
(1966). Glucose tolerance test. Variability in pregnant and nonpregnant woman. American Journal of Clinical Nutrition, 19, 345–351. https://doi.org/10.1093/ajcn/19.5.345
(2014). R: A language and environment for statistical computing. Vienna, Austria: R Foundation for Statistical Computing. Retrieved from http://www.R-project.org/
. (2015). foreign: Read data stored by Minitab, S, SAS, SPSS, Stata, Systat, Weka, dBase, … Retrieved from http://CRAN.R-project.org/package=foreign
. (2012). The ironic effect of significant results on the credibility of multiple-study articles. Psychological Methods, 17, 551–566. https://doi.org/10.1037/a0029487
(2015). DescTools: Tools for descriptive statistics. Retrieved from http://CRAN.R-project.org/package=DescTools
(2009). Insulin detemir causes increased symptom awareness during hypoglycaemia compared to human insulin. Diabetes, Obesity & Metabolism, 11, 1017–1026. https://doi.org/10.1111/j.1463-1326.2009.01085.x
(2016). The bitter truth about sugar and willpower: The limited evidential value of the glucose model of ego depletion. Psychological Science, 27, 1207–1214. https://doi.org/10.1177/0956797616654911
(2004). Use and abuse of HOMA modeling. Diabetes care, 27, 1487–1495. https://doi.org/10.2337/diacare.27.6.1487
(2016). Glucose metabolism and self-regulation – Is insulin resistance a valid proxy of self-control? Personality and Individual Differences, 99, 38–45. https://doi.org/10.1016/j.paid.2016.04.070
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