People who get "hangry" share two genes linked to neuroticism and schizophrenia, new research from DNA-testing company 23andMe has revealed.
Just yesterday, a psychological study on hangriness found that the feeling doesn't just arise when hunger does, but depends almost entirely on one's emotional state.
According to the Daily Mail, the makers of the popular at-home genetic testing kit have begun to leverage their sprawling database for research on everything from eating habits to pain tolerance and depression.
According to 23andMe's survey of 100,000 people, 75 percent of us get that hangry feeling at least occasionally.
To the surprise of the research team, getting "hangry" - a term coined for people who get particularly angry and irritable when they need to eat - actually had very little, genetically speaking, to do with metabolism.
Being hangry - a word made from mashing up "angry" and "hungry" that made its way into the Oxford English Dictionary this year - sounds like something that could happen to anyone, but the new research suggests we're not all susceptible to it.
Of the 75 percent of hangry people, the majority were women, and young.
In fact, about 70 percent of people over 50 said that they had never felt hangry in their lives.
At first blush, this might suggest that the highly-irritable state is just a new concept, but the 23andMe team found that it does indeed have roots in DNA, just not the ones they were expecting.
"We thought that if there was an underlying genetic reason for getting hangry that it would potentially be related to hypoglycemia or low blood sugar," said Janie lead data scientist on the study, Janie Shelton.
Having how blood sugar does mean that your brain is being deprived of its energy source, which can have a destabilising effect on your mood and make you cranky, down and irritable.
But that turns out to be a separate issue from being hangry.
Instead, they found that hangriness is more linked to two genes "more related to mental health and personality that, to my knowledge, have never been published before," she added.
To establish this, she and her team sent surveys about eating behavior to 100,000 of the people that had already submitted their DNA to 23andMe through a cheek swab and agreed to take part in the company's research projects.
The survey asked people questions on "emotional eating behavior, snacking, binge eating and how satisfied they are, and about becoming angry or irritable."
Once they had collected this information, the researchers compared the self-reported data to the DNA samples each person had previously sent into 23andMe.
To their surprise, those who got hangry shared two variants of two genes that have nothing to do with metabolism and blood sugar, but with psychology.
"There were two genes that showed up very differently in the hangry people: VRK2 and ERI1," explains Shelton.
"ERI1 is linked to subjective well-being, irritability and neuroticism, and all of these are largely features of personality and mood."
The second gene, VRK2, has been linked to conditions like schizophrenia, depression, epilepsy and multiple sclerosis.
"Both genes are more neurophysiological than metabolic," says Shelton.
"So this [hangry] response is something we consider part of constitution or mood, not so much a unique response [to hunger]."
Though it may not follow intuitively, their genetic findings on hunger come just after another study from the University of North Carolina that found that getting hangry is all about context and emotional self-awareness.
Taken together the two studies show that our feelings and psychology are involved in even the most basic bodily functions, like eating.
