Friday, November 16, 2012

Carbs and self control.

From Molden et al. suggest the increase in self control that some studies have correlated with carbohydrate consumption is caused not by a metabolic energy boost, but rather by an increase in motivation:

Self-control is critical for achievement and well-being. However, people’s capacity for self-control is limited and becomes depleted through use. One prominent explanation for this depletion posits that self-control consumes energy through carbohydrate metabolization, which further suggests that ingesting carbohydrates improves self-control. Some evidence has supported this energy model, but because of its broad implications for efforts to improve self-control, we reevaluated the role of carbohydrates in self-control processes. In four experiments, we found that (a) exerting self-control did not increase carbohydrate metabolization, as assessed with highly precise measurements of blood glucose levels under carefully standardized conditions; (b) rinsing one’s mouth with, but not ingesting, carbohydrate solutions immediately bolstered self-control; and (c) carbohydrate rinsing did not increase blood glucose. These findings challenge metabolic explanations for the role of carbohydrates in self-control depletion; we therefore propose an alternative motivational model for these and other previously observed effects of carbohydrates on self-control.

10 comments:

sunejakobsen said...

What evidence is there that self-control is depleted through use?

Deric Bownds said...

I think perhaps a better word than depletion would be tiring, or fatiguing (in resisting some kind of temptation), just as muscles do with use.

Cleo Yusainy said...

Interesting summary, Deric. To be honest I am still confuse about the differences between self-control depletion and tiredness or fatigue, but I don't think they are identical. For instance in a recent study that directly measures the effect of sleep deprivation for 24 hours and self-control depletion (using suppressing emotions task) on aggressive behaviour(a typical behaviour that requires self-control), the researchers finds that depletion alone increased aggressive behaviour, irrespective of fatigue (sleep deprivation) condition.

sunejakobsen said...

So it there evidence that if we use self-control to resist something we will have less self-control in another task afterwards?

Deric Bownds said...

I'm in over my head here. I really don't know the literature that might answer your question. I suspect relevant experiments are out there somewhere.

LCK said...

http://www.psychologytoday.com/files/attachments/584/baumeisteretal1998.pdf

http://paul.kedrosky.com/archives/2011/08/ego-depletion-and-decision-fatigue.html

http://www.nytimes.com/2011/08/21/magazine/do-you-suffer-from-decision-fatigue.html?_r=1&hp=&pagewanted=all

http://brain.oxfordjournals.org/content/133/4/1265.full.pdf+html

http://pss.sagepub.com/content/early/2010/03/11/0956797610364968.abstract

Deric Bownds said...

Thanks for the references... interesting.

Jim Birch said...

Hasn't carb mouth rinse been demonstrated to improve muscle output too? The inference would be that the "system" detects that replacement energy is coming so it's ok to deplete muscles or brain a bit more than otherwise preferable.

This seems to me to be likely to be highly relevant to the obesity explosion. Current explanations like exercise and food availability don't quite explain the historical shift. However, if you add information overload - tv, internet, working styles - to the equation it could all make sense. A lot of people might have reached the limit of their ability to process information without relentless snacking.

Deric Bownds said...

Interesting point!

Anonymous said...

thanks for sharing

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