The Cooper Institute

Founded in 1970 by the "Father of Aerobics"
Kenneth H. Cooper MD, MPH


Self Control and Blood Sugar: Part 3

Written by
Kate Edwards, PhDc
Posted in
Eat better

Thursday, Aug 09, 2012

Last week, we discussed the Strength Model of Self-Control, or the idea that self-control is similar to a muscle that can be fatigued with overuse.  Also, similar to a muscle, self-control can be strengthened through “exercise.”  These exercises can include activities like staying on the treadmill for an extra 5 minutes or changing a behavior that is as simple as paying attention to your posture.  But, what if I told you there might be another way you can maximize the amount of self-control you have throughout the day?  Well, Galliot and colleagues believes there is . . . with food.

In their research, Galliot and colleagues asked people to take part in several activities that require self-control.  These activities included trying not to think about a white bear and stopping themselves from crying or laughing during a sad or funny movie.  Before and after the self-control activity, the participants’ blood sugar was taken.  What they found was that participants who took part in the self-control activities showed a significant drop in the amount of sugar in their blood compared to participants who just sat for 5 minutes and pressed a button on a keyboard.

Remember when we talked about how people who take part in a self-control activity are likely to do worse on a second self-control activity?  Well, Galliot and colleagues thought that this drop in blood sugar might be the reason why.  They also asked themselves that if there is a drop in blood sugar after the first self-control task, what might happen if they “refill” or “reload” the amount of sugar in the blood.

They gave a group of the participants lemonade sweetened with real sugar and gave the other group lemonade sweetened with a similar tasting sugar substitute.  Both groups then completed another self-control activity.  Almost not surprisingly, the group that was given the lemonade sweetened with real sugar, which raised their blood sugar, performed better on the second self-control activity than the group that was given the lemonade with the fake stuff, which did not raise their blood sugar.

So basically this means that if you are using your self-control muscle (staying awake during a boring lecture or resisting that tempting cookie) you might be using up your blood sugar.  You can see the effects of this, say, when you get cranky with a loved one after a long day of work and then you eat dinner, you feel better and apologize.

This research may suggest that the long standing advice of spacing out meals throughout the day may help you keep your blood sugar levels even, which in turn can keep you in control.  But BEWARE!  The more sugar you have in your blood does not necessarily mean more self-control.  As with most anything, there is a limit and you can cause more harm than good if you overload on sugar.  For example, eating a candy bar when you’re feeling your blood sugar may be low may not be a good idea.  Can we say sugar crash and burn?  Some healthier options to snack on may be a handful of nuts with some berries or an apple with peanut butter.  Having well balanced snacks can keep your blood sugar even throughout the day and help you resist eating that half a chocolate cake when you get home from a long day at work.

Galliot, Baumeister, DeWall, Maner, Plant, Tice, Brewer & Schmeichel (2007).  Self-control relies on glucose as a limited energy source:  Willpower is more than a metaphor.  Journal of Personality and Social Psychology, 92 (2), 325-336. doi: 10.1037/0022-3514.92.2.325