‘Hangry’- the science behind the mood when you’re craving food

If you have ever snapped at a partner or become especially irritated with a co-worker when you are hungry it is likely you have experienced ‘Hanger’, the phenomenon of short temper and increased irritability experienced when famished. As the famous tag line for chocolate brand Snickers goes ‘You’re not you when you’re hungry’. However there is a scientific reason for this increase in grumpiness and lack of emotional self-control when your body is craving food and its due to glucose, a simple sugar found in the diet.



Glucose- the sugar that keeps you calm?

Similarly to in diabetics where not enough glucose (hypoglycaemia) in the body can lead to irritability, confusion and difficulty concentrating, periods of short term starvation can have negative effects on the brain. Although the body can adapt to periods of long term starvation by producing ketone bodies, the brain tends to rely on glucose for short term energy as fats are too large to pass through the blood-brain barrier. The brain uses about 120 grams of glucose a day and, even when running on ketones, it still requires 30 grams of glucose. One of the most important parts of the brain regarding the ‘hangry’ process is the Pre-Frontal Cortex which modulates executive function, important in self-control and moderating social behaviour. This means that when the pre-frontal cortex is starved of glucose, for instance when you are hungry, it can be harder to demonstrate self-control. Therefore, there is increased likelihood of snapping or being unable to control anger. Bad news for those around you!


There is another reason why a lack of glucose can lead to the ‘hangry’ feeling and that is centred around the hormonal response to low blood glucose concentrations. The body will react to low glucose concentration, which occurs when your body has been given insufficient food, by trying to take glucose from the body’s stores in a process known as the glucose counter-regulatory response. When the receptors in the body detect threshold glucose concentration of about 3.9 mM it will react by releasing hormones to counteract the hypoglycaemic (low blood sugar) state your body finds itself in; Glucagon, Cortisol and Adrenaline. Wondering where you’ve seen that last one before? Adrenaline is a catecholamine essential for the fight or flight response. The body reacts to stressful situations by entering ‘survival mode’ and releasing adrenaline from the adrenal glands. This causes quickened heartbeat, faster breathing and, importantly regarding ‘Hanger’, a tenseness in your whole body. The same thing happens when the body releases adrenaline when hungry, meaning you get the same tension seen in the fight or flight response. This is an adaptation for survival, when in danger your body needs to be in a state ready to act and survive and, similarly, when you’re hungry you need to be ready to seek out food in order to live by foraging or hunting. Basically, being ‘hangry’ keeps you alive! If that’s not an excuse for being a bit moody when you’ve missed a meal I don’t know what is!

It’s in your genes

Another cause of the ‘hangry’ phenomenon is to do with the neuropeptides and receptors in your brain. Neuropeptide Y, important in feeding regulation, is orexic, meaning it drives feeding. Neuropeptide Y, however, is also important in regulating anger and aggression. This means that the same mechanism that makes you hungry can make you angry! A 2012 paper linked high circulating Neuropeptide Y levels with impulsive aggression and the level was higher in those with an anger personality disorder.

Is it just me?

Don’t worry it’s not just you who gets ‘hangry’, just ask anyone starting out a diet (or those around them!). Actually, there have been several studies confirming the link between being hungry and being in a mood. A 2014 study of 107 married couples showed that those with low blood sugar blasted their partners with unpleasant noises at a higher volume and stuck more pins in voodoo dolls of their spouse to represent their anger. Creepy! An older study, less representative of a 2000s-horror movie, from 1995 showed those with hypertension (high blood pressure) showed significant increases in tension measured by the UWIST Mood Adjective Checklist, whilst other research papers have confirmed the link between hypoglycaemia and irritability and moodiness.


How do I stop it?

If you are often upsetting those around you by showing frequent bouts of ‘hangry’ mood swings we have a solution! And a simple one. EAT. Slightly more complicated is what we recommend to eat. Getting that quick fix to solve your hanger can be a problem as junk foods induce large rises in blood-glucose levels that come crashing down fast and could, therefore, increase your problem. However, pairing faster release carbohydrates such as bananas to get your blood glucose up fast with slower release carbohydrates such as Non-Starchy Vegetables, Sweet Potatoes or nuts to keep them maintained over a longer period of time could be the magic cocktail in stopping you snapping as your body is craving food. So, eat sensibly and save those around you from your ‘hangry’ side!



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