A recent study at the Florida State University revealed that glucose affects our ability to resist temptation and makes self control more difficult.
Florida State psychologist Roy F. Baumeister along with his colleagues showed this with an experiment using the Stroop task, a famous way of testing strength of self-control where the participants in this task are shown colour words that are printed in different-colour ink (like the word red printed in blue font),
The participants are then told to name the colour of the ink, not the word.
Baumeister found that when participants perform multiple self-control the ability to control themselves diminishes as it is exercised.
They found that the sugar, in form of glucose reduces the self-control ability.
The researchers measured the blood glucose levels of participants before either engaging in another self-control task or a task that did not involve self-control.
They found that the group performing the self-control task suffered depletion in glucose afterward.
Moreover, in another experiment, two groups were asked to drink sweetened beverages in between, while performing the Stroop task.
The control group drank lemonade with Splenda, a sugar-free sweetener; the test group got lemonade sweetened with real sugar.
The sugar group performed better than the Splenda group on their second Stroop test, apparently because their blood sugar had been restored.
"For one thing, like muscles, self-control may be able to be strengthened through exercise. Results so far are inconsistent and some regimens work better than others" Baumeister said.
Baumeister anticipates that greater understanding of the biological and psychological keystone of our ability to control ourselves will have important real-world application for people in the self-control business, such as coaches, therapists, teachers, and parents.