Anyone who has ever lashed out at a coworker after working through lunch, or screamed at a boyfriend before dinner but suddenly felt much better after the meal, might be familiar with notion of being hangry. A combination of "hungry" and "angry," hangry is the state you find yourself in when your body has been deprived of glucose and, as a result, sends messages to your brain to behave aggressively. "Self-control consumes a lot of glucose in the brain, suggesting that low glucose and poor glucose metabolism are linked to aggression and violence," wrote the authors of a study on the subject that was published in the journal Aggressive Behavior.
Dr. Amanda Salis, associate professor at the Boden Institute at the University of Sydney, told the Huffington Post that hanger is probably a survival mechanism. "If our predecessors just stood back and politely let others get to the food before them, there is a good chance that they may not have gotten enough to eat, and they would have died — possibly before they could pass their genes on to the next generation," she said. "So it was likely the individuals that were aggressive when hungry that had a survival advantage, and we hence carry their genes to this day, whether we live with a shortage or abundance of food."