The state of being hangry - or being grumpy and irritated when one is hungry - is actually real, and there is a scientific explanation for it, according to The Conversation.

The term "hangry" is a combination of the words "hungry" and "angry" and was coined to describe how some people become irritable and angry when they are hungry.  

Based on the research done by Amanda Sainsbury-Salis, a National Health and Medical Research Council senior research fellow at University of Sydney's Boden Institute of Obesity, Nutrition, Exercise and Eating Disorders, the state of being hangry has something to do with a person's blood glucose levels.

All food intake is converted into simple sugars, amino acids and free fatty acids, and these get distributed to different parts of the body through the blood. When the next meal is skipped or delayed, the amount of these substances in the blood begins to drop.

At a certain point, when the level of these substances becomes too low, the brain, which primarily depends on glucose for energy, alerts the body that it is in a life-threatening situation.

Hunger causes people to have difficulty concentrating or finding the right words to say. The drop of glucose in the brain also causes people to drop socially acceptable behavior, which makes them grumpy and irritable, according to The Conversation.   

A study published in 2014 says that this tendency to let go of socially acceptable behavior when hungry is expressed in greater intensity toward those with whom the hungry person is closest, such as one's spouse or friends. A hungry person finds it hard, to some degree, to practice self-control because self-control requires energy from glucose, and a hungry person has dropping levels of glucose.

Sainsbury-Salis also explains that hunger causes the body to go into a glucose counter-regulatory response, which simply means that the brain instructs some organs to release hormones that will increase the level of glucose in the bloodstream. These include the stress hormone adrenaline.

Adrenaline is responsible for putting the body in a "fight or flight" mode when a person is caught in life-threatening situations. It is not uncommon for people to raise their voices against each other in the face of an emergency.

In the same way, the body copes with hunger by releasing adrenaline and putting it in a similar "fight or flight" mode, making a hungry person snap at others when he or she normally wouldn't.

Finally, anger and hunger are regulated by similar genes. Neuropeptide Y and the Y1 receptor both control hunger and regulate aggression and anger. Thus, people with high levels of neuropeptide Y in their cerebrospinal fluid also show greater aggression, according to a study published in the U.S. National Library of Medicine.

So how does one avoid being hangry? Science offers a very simple solution - eat before you get too hungry. And remember to engage in sensitive and difficult discussions after eating, not before.