We know that pretty much anyone can give you anecdotal evidence that being hangry is a real thing. Hangriness is how you get to scenes like this in real life:

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Good news: several recent scientific studies have correlated low blood sugar with the phenomenon of hangriness. Vox dug into a few of these, which revealed some interesting findings:

  • In a study published in the Proceedings of the National Academy of Sciences, researcher Brad Bushman and his team studied 107 married couples over 21 days. The study found that abnormally low blood sugar episodes resulted in spouses that were more likely to be angry with one another. Subjects also became more aggressive. Researchers used voodoo dolls and headphones playing loud, annoying sounds for spouses to demonstrate their anger and aggression.
  • Separate, unrelated tests either gave subjects sugar (in the form of lemonade), or else reduced blood sugar levels (by using insulin) and then observed their subjects. Subjects given lemonade weren’t very aggressive when compared to those who were given a placebo instead, and other subjects given bonus sugar were less likely to be frustrated by a very difficult computer game. Meanwhile, subjects in the test that used insulin tended to have “more negative moods.”

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As often happens, there is still some skepticism about these findings. As the magazine Science reports, psychologist David Benton of Swansea University—who studies dietary influences on brain and behavior when he’s not throwing scientific shade—found the PNAS study less than impressive.

He told Science

“Based on previous better conducted studies it seems that low blood glucose can be one of many factors that predispose to aggressive behavior.”

Then Benton pointed out that alcohol consumption can both lower blood glucose levels and result in aggressive behavior, but the study neglected to collect information on what subjects ate and drank. Benton went on to add that taking a single measure of dynamic response, at different times in different people, will tell us little.”

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But a separate, slightly older study from PNAS involved eight Israeli judges who were asked to grant or deny prisoners parole. Vice reports that at the beginning of the day, after eating breakfast, the judges were granting nearly two thirds of prisoner parole requests. By the time just before their next meal, the number of paroles granted was nearly zero. To underscore these results, the number of parole requests granted went back up to two-thirds directly after lunch.

Several years ago, the New York Times reported that humans and other animals have increased senses of alertness when they’re hungry. Dr. Mark Friedman of the Monell Chemical Senses Center in Philadelphia, said, [pullquote]”Your sensitivity to your external environment increases,” These sorts of needs open sensory gates. [That may be why] someone playing music in the apartment below may be more irritating when you’re hungry than when you’re not.”[/pullquote]

Bottom line: eat something, avoid crankiness, and possibly avoid ruining some prisoners’ lives. It really does seem to be that simple.

[via Vox, Science, Vice, NYT]

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