You Won’t Like Me When I’m Hangry

A lack of nutrition doesn’t just make you tired. It can also shorten your fuse. Low blood levels of glucose are tied to impaired self-control, research has shown. As a result, the glucose-deprived may be inclined to lash out at those who frustrate them—including, a 2014 study finds, their romantic partners.

In an experiment with 107 married couples, Ohio State University psychologist Brad Bushman and colleagues asked participants to measure their blood glucose nightly. They also gave every participant a voodoo doll. The instructions: to insert up to 51 pins in it every night, depending on how angry each was with his or her spouse.

When participants had relatively low levels of glucose in their bloodstream, they pushed about three times as many pins in the doll, according to Bushman. In a later laboratory task, when given the chance to blast their partner with an unpleasant sound after winning a game, those with lower average nightly levels of blood glucose exposed partners to a longer and more intense noise.

“The emotion that people have the most difficulty regulating is anger, and the fuel the brain needs to regulate emotions comes from glucose,” Bushman says.

When a contentious topic is up for discussion, a nutritious energy boost could pave the way for a smoother conversation. In a study published in the journal Aggressive Behavior, subjects who drank lemonade sweetened with glucose-rich sugar demonstrated less aggression in a noise-blast experiment than those who drank lemonade containing a sugar substitute.

Not that pure sugar is the best solution. Psychologist Matthew Gailliot, who co-authored the study, recommends a diet with plenty of whole grains, fruits, and vegetables for optimal glucose levels.

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