An advertising campaign for a popular candy bar uses the phrase "you're not you when you're hungry" in humorous commercials with miscast celebrities acting in offbeat ways. According to recent research at Ohio State University, the candy manufacturers might be on to something.
The researchers studied 107 couples over a three-year time period and found that higher levels of aggression and anger between married couples were connected to low blood glucose levels. Their work was published in an online version of the Proceedings of the National Academy of Sciences.
For three-week periods, the subjects measured their glucose levels twice daily - prior to their morning breakfast and at bedtime. They were also asked to stick pins into voodoo dolls representing their spouse and write down the number of pins used - thus serving as a measure of anger at their spouse at day's end.
The group found that the quartile of subjects with the lowest blood glucose levels averaged twice the number of pins stuck into the voodoo dolls of their spouses when compared to the quartile with the highest glucose levels.
In a follow-up experiment, the married couples played a computer game that pitted them against their spouse - or so they thought. The researchers rigged the computer game to ensure that each spouse would win an approximately equal number of times.
At the end of the game, the winning spouse was able to subject their spouse to a loud and unpleasant noise such as sirens and fingernails against a chalkboard. Within some limitations, they could supply the noise as long as they wanted and make it as loud as they wanted. Blood glucose levels were measured during this game.
The results were similar to that of the voodoo dolls - volunteers with the lowest quartile of blood glucose sugars subjected their spouses to longer and louder noises.
Couples that reported having contented relationships were just as likely to show higher aggression levels with lower blood glucose, ruling out the baseline state of the relationship as a factor.
The research team suggests that a lack of glucose deprives the brain of the energy that it requires to maintain self-control. In turn, this leads to higher levels of aggression.
These aren't extremely surprising findings - connections between low blood sugar and aggression have been suggested for some time. After all, the candy-bar advertisers had successfully made the connection without the benefit of this research.
Other scientists have suggested that blood glucose levels are likely a factor in this aggression, but they are not necessarily the only factor, or even the dominant factor. For example, while glucose levels were tested, information about the subject's diets was not collected. Alcohol could trigger both lower glucose levels and aggressive behavior.
While this work is not definitive, it does suggest that couples should have not important discussions on an empty stomach - and that aggressive tendencies can be at least somewhat checked with a proper diet. That may or may not include the occasional well-advertised candy bar.