Appliance of Science: Why do we get hangry?

This week’s question comes in from Niamh, from Galway, who would like to know…

Appliance of Science: Why do we get hangry?


I can empathise with this one, being a sufferer myself (or those that are near me during my hangry episodes may argue that it is they that suffer).


The term is an amalgam of ‘hungry’ and ‘angry’ and refers to people who get irritable when they need to eat.


Hunger can interfere with our concentration and make us more likely to snap at people around us, so why is that? There are a number of contributing factors but the primary reason comes down to brain food.

We break down the food we eat into smaller components that can fuel the body. One such component is the simple sugar, glucose, the brain’s primary fuel. If we leave too much of a gap between meals then we risk our blood glucose levels dropping. This affects people in

different ways; for some it triggers a strong response in the brain that makes us hangry. The brain needs fuel to regulate and control

emotions, particularly anger.

It is understandable that we get irritable when the brain’s main food runs into short supply. From an evolutionary standpoint this is a threat to our survival. If we need food, and need it now, then it is not a time to be timid. But the reaction is not just physiological, it can be neurological and psychological too.


A drop in blood glucose levels can trigger the release of certain hormones that control our appetite; these include cortisol and adrenaline. These two hormones have other functions as well, particularly in

eliciting the fight or flight mechanism in response to stress and anxiety. Anger is often a side effect expressed in situations where the body feels under stress.


There is also a genetic link between the control of hunger and the regulation of emotional responses, such as anger. Certain genes control both processes, for example, neuropeptide Y is produced by one such gene; this neurotransmitter is secreted into the brain in response to hunger. Neuropeptide Y acts on more than just one area of the brain; it causes a response in the hypothalamus, the area that controls appetite but it also triggers a response in the amygdala, the region that regulates our emotions, including anger. High levels of neuropeptide Y therefore increase both our wish for food and our levels of stress and frustration.


It is interesting that the stress and the appetite responses are controlled by similar processes. This not only accounts for hunger triggering an emotional response but also backs up the research that reports how we often reach for food when feeling stressed or anxious; it seems the stress-appetite response may go in both directions.


Given the complexity of different processes that contribute to hanger, it would be normal to have a spectrum of different responses.

Naomi Lavelle is a science communicator and mother to three inquisitive children. She can be found at

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