Eat up! Low levels of glucose might hurt your sweetheart


A new study found low glucose levels to be associated with higher aggressive impulses and behavior towards intimate partners.

You get home from a long, busy day at work. You haven’t eaten anything since the muffin that you grabbed on your way out the door this morning. You are tired, you are hungry, and you are irritable. Naturally, you lash out at your spouse. But why?

Previous research has found a strong positive correlation between low levels of glucose and reduced self-control. Self-control is a necessary mechanism when it comes to handling our anger and aggressive impulses. Thus, lower levels of glucose relate to an increased difficulty in overriding aggressive impulses. In line with these findings, a new study sought to investigate the effect that glucose levels might have on intimate partner relations. The study, published this week in Proceedings of the National Academy of Sciences, found that low glucose levels are associated with greater aggression and violent tendencies in intimate relationships.

The study measured aggressive impulses and aggressive behavior in heterosexual couples. To measure aggressive impulse, the researchers gave each participant a voodoo doll  that was meant to represent his or her spouse. The participants were told that at the end of each day for three weeks, they were to privately push pins into the doll. The number of pins pushed should depend on the amount of frustration or anger they were feeling towards their spouse that day. The participants also measured daily glucose levels.

At the end of the 21 days, participants were brought back to the laboratory. Here, aggressive behavior was measured.  Participants were told that they were competing against their partner in a computer game, when in actuality they were competing against the computer). The winner was allowed to blast a loud, undesirable noise through headphones to the loser.  The participant had control over the duration and volume of the noise. As the researchers predicted, lower levels of glucose were related to more aggressive impulses and behavior. The lower the glucose levels, the more pins the participant stuck into the voodoo doll. Furthermore, participants who had had lower glucose levels punished their spouses more with louder noises and for a longer period of time.

The researchers suggest that the findings have implications beyond intimate couples, such as interventions that provide more food in places like prisons, psychiatric hospitals, and schools. For example, due to poor food quality, many kids do not eat their school lunches and go hungry throughout the day. Teachers then wonder why they are disruptive in class or have trouble concentrating. According to these findings, a little bit of food might very well do the trick to replenish self-control, reduce conflict, and keep everybody on task.


Brad J. Bushman, C. Nathan DeWall, Richard S. Pond, Jr., and Michael D. Hanus.Low glucose relates to greater aggression in married couplesPNAS, April 14, 2014 DOI: 10.1073/pnas.1400619111

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