A psychology study (subscription required) in the current issue of the Proceedings of the National Academy of Sciences struck down sugar's power to rule over those struggling with self-control - so long as people believe that their willpower is greater than their glucose stores.
The study examined the role of glucose ingestion and attitudes about willpower in self-control and cognitive performance. Psychologists from Stanford and the University of Zurich conducted three experiments testing theories about willpower, including past research showing that taking in glucose increases self-control. From the study:
...following a demanding task, only people who view willpower as limited and easily depleted (a limited resource theory) exhibited improved self-control after sugar consumption. In contrast, people who view willpower as plentiful (a nonlimited resource theory) showed no benefits from glucose—they exhibited high levels of self-control performance with or without sugar boosts. Additionally, creating beliefs about glucose ingestion (experiment 3) did not have the same effect as ingesting glucose for those with a limited resource theory.
As Stanford psychologist and study author Carol Dweck, PhD, tells the Stanford Report:
"When you have a limited theory of willpower, you're constantly on alert, constantly monitoring yourself. 'Am I tired? Am I hungry? Do I need a break? How am I feeling?' " Dweck said. "And at the first sign that something is flagging, you think, I need a rest or a boost."
She said people who have the more-abundant theory aren't looking for those cues all of the time.
"We're not saying people don't need fuel for strenuous work, they just don't need it constantly," Dweck said. "People have many more resources at hand than they might think."
Previously: Examining how stress affects good and bad habits, Ask Stanford Med: Answers to your questions about willpower and tools to reach our goals, Ask Stanford Med: Stanford health psychologist Kelly McGonigal taking questions on willpower, The science of willpower and Addiction: All in the mind?
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