Why being hungry puts us in such a bad mood?

You probably have noticed that your bad mood increases considerably while you are hungry. Maybe if it has not happened to you directly, you sure know some people who get a little irritable when their stomach starts to roar. Don’t worry, it’s not like you’re becoming The Grinch, everything has a scientific explanation. In fact this is nothing more than a natural reaction in every one of us. Who hasn’t heard a baby cry when he is hungry? Yes, they do it to get attention and get fed, but also because their empty stomach makes them grumpier.

As a matter of fact, it’s so common for people to get mood swings while having an empty stomach that there is even a famous term to define it: “hangry“. Which is a conjunction between “hungry” and “angry“. In order to make you understand this better, we will explain what happens to our body when we are hungry and how it affects our brain.


Why do we get hungry?

The food we eat is broken down by our body in a series of nutrients, such as sugars, proteins, fats, etc. Among these groups of nutrients, we got glucose being absorbed directly by our bloodstream and distributed throughout our body made up as immediate energy for our cells.

Glucose is the main “energy source” for our brain. Its functioning depends to a large extent on the level of glucose, since this nutrient is easy to be transported and delivered to the brain. Therefore, a low blood glucose level would blow all the alarms in our body. The brain is the first to detect when something isn’t right, especially when it has less energy to function. At this moment is when the problems begin. We think more slowly, it is hard for us to concentrate and it diminishes our attention span.

In addition to these signals that our brain is sending us, while we are hungry we suffer another series of more tangible signals, such as noises made by our stomach. Many times these noises become very annoying and can even cause pain. They also tend to be quite uncomfortable socially speaking, since sometimes they can be audible by other people. This probably happened to you while in a classroom or at work, and you wanted the earth to swallow you.

These signals make our mood start to change. We can feel very grumpy and we become much more irritable. At that point, we don’t even want to interact with people anymore.

How does our brain act while we’re hungry?

When our blood glucose goes down, our brain activates a series of counter measures. These signals are orders from our brain, telling our body to release hormones that demand more sugar into our bloodstream. These hormones mixed with the lack of energy are the ones that really cause this really bad mood.

Among these hormones, we have glucagon involved, which is responsible for metabolizing glycogen. With this hormone, our brain will tell our organism to burn all stored reserves of sugars. Then there’s the growth hormone, and finally we have adrenaline and cortisol. These last 2 are precisely the hormones that usually come up during stress episodes. When a person goes into a stressful situation, their body goes on alert mode, because they know something isn’t going right. Adrenaline and cortisol are the cause of our body sending glucose into the muscles, to have the necessary energy always prepared if any situation of danger comes up.

In addition to these stress hormones, there is another substance that participates in the regulation of fats. That could explain our rage by not eating. This substance is Neuropeptide Y, which certain studies have shown that people with high levels tend to be more aggressive.

So if at any time you feel more aggressive than usual, try to improve your blood glucose level before making any decision or having a discussion with another person.

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