Why do people get hangry? A study suggests it’s not just low blood sugar to blame

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We’ve all been there, hungry, irritable, and angry, or “hangry,” a term added to the Oxford English Dictionary in 2018, after decades of accepted usage among bickering partners and frustrated colleagues across the English-language world.

But how hunger mutates into anger is still not entirely clear to scientists. Recently, two researchers at the University of North Carolina Chapel Hill set out to study the underlying mechanism. Their results challenge the going theory that hanger is essentially the result of low blood sugar making it harder for people to control their emotions (known as the regulatory depletion hypothesis.)

While that may be part of the story, “there’s probably other things psychologically going on,” says Jennifer MacCormack, lead author of the study and a PhD student studying psychology and neuroscience at UNC. ”Otherwise, why wouldn’t hunger always lead to us lashing out or being terrible human beings?”

Hunger does lead to higher levels of cortisol and adrenaline in the body, making you feel tense and stressed out. According to the research, however, hunger-induced feelings can lead to tantrums and anger when someone is in a situation that is indeed somehow stressful (so your family or co-workers may not be entirely off the hook), and the person experiencing hanger is unaware of their bodily state. The combination creates “the perfect storm” for someone to misattribute their pangs to an external source.

“Because of the stress, for example, or the provocativeness of the situation, people are really focused on what’s happening,” and not on their own physiological state, MacCormack says. So it becomes, “You’re the terrible reason I’m angry,” she says.

The new study, published this month in the journal Emotion, was divided into three parts: In two experiments, online participants were asked to rate the pleasantness of Chinese characters that were unfamiliar to them, with the characters serving as inkblots, or ambiguous stimuli. (Any participants who knew Chinese were excluded from the study.) Before rating the characters, however, they were flashed pictures of objects that are considered neutral (for instance, an iron), positive (a kitten, perhaps), or negative (a threatening cougar, for example). Later, they self-reported their hunger levels.

It turned out that only hungry people who also saw a negative image read the subsequent Chinese characters as less than pleasing to the eye.

Next, the researchers invited 200 students to a lab experiment sold as a “visual performance” test. They asked half to fast beforehand, and they ran the students through a series of exercises. Half the group was asked to write about an emotional experience, something sad or angry, while others wrote on a neutral topic. Then all the students were asked to complete a long, “tedious” test on a computer that was set up to crash just before they could finish, at which point, a miffed researcher would enter the room, asking the student, “What did you do?!”

That bothered some people, sparking feelings of ill-will for the researcher. But not everyone was rattled, only those who had not been directed to write about their emotions. People who had fasted, but had been primed to think about emotions, were no more angered by the crashed computer and the researcher’s unjust insinuation than people who had eaten before the test.

Like any study, this one has its limitations, and the researchers say it’s just meant to help us begin to understand the complicated “hangry” reaction. Even if you’re not the type to get hangry, they caution, when hunger pangs hit, it might lead to other negative emotions, like stress or disgust, in the right context. A closer examination of these connections could help scientists understand the “downstream emotions” that follow hunger states in different populations, the authors argue, including those with diabetes or the elderly, who may not be able to sense their hunger.

MacCormack suggests becoming better aware of your hunger as a way to avoid blaming your hot head on the situation around you. And what if it’s too late, you’re stuck in traffic after someone cuts you off, or you’re marooned at your desk after a tense budget update, and now you’re in hangry mode?

“In these cases,” MacCormack writes in The Conversation, “try to make your environment more pleasant. Listen to an amusing podcast while you drive. Put on pleasant music while you work. Do something to inject positivity into your experience.”

And, you know, start packing snacks.