When the body is deprived of blood glucose (which tends to happen when meals are skipped) the brain receives all kinds of signals to behave aggressively. Snapping out at partner or in some cases strangers happens because aggressive and violent behaviors are restrained by self-control. Self-control consumes a lot of glucose in the brain, suggesting that low glucose and poor glucose metabolism are linked to aggression and violence. A low blood sugar supply to the brain has other negative side effects.
The strain of exercising self-control all day long uses a lot of energy, using a lot of glucose. When there is a lack of food to be broken down there is a shortage of glucose, but there is more to it than that. The body tries to compensate when blood glucose decreases by releasing certain hormones, like cortisol and adrenaline (which can increase aggressiveness).
Fatigue and impaired concentration is also a side effect, which doesn’t necessarily need to have an aggressive response to low blood sugar. If getting “hangry” is a real problem for some people they should stay on top of their hunger pains, and try to eat regularly. Healthy snacks like fruits offer the body lots of easily accessible sugars and have other nutritional benefits.
Source: “The Science Behind Why You Get Hangry.” The Science Behind Why You Get Hangry. Web. 17 Feb. 2016.