Today’s Wonder of the Day was inspired by Tyler. Tyler Wonders, “Why do you get hungry?” Thanks for WONDERing with us, Tyler!

It's Monday morning. You drag yourself out of bed and trudge slowly through your morning routine. After a fun family weekend, you're not quite ready for school to start. In fact, you're running so late that you forget to eat breakfast before you run for the bus.

Your tummy starts rumbling late in the morning. You steal glances at the clock, counting down the minutes until lunch. You say a quick prayer, hoping that you'll soon be feasting on pepperoni pizza or chicken nuggets.

When you get to the lunch line, however, you're dismayed to see your old nemesis on the tray: Salisbury steak. No matter how many times you've tried, you just can't seem to develop a taste for it. You pick at your mashed potatoes and peas and eat all of your fruit cup.

As the afternoon wears on, you feel irritated. At recess, you snap at your friends and they ask you why you're so mad. You don't know what to tell them. You're just hungry. And now angry. You're hangry!

"Hangry" is what linguists call a portmanteau: a word whose form and meaning come from blending two or more other words. In this case, the words are hungry and angry, giving hangry its meaning: irritable or bad-tempered as a result of hunger.

Hangry has become a popular term over the last several years. However, its first use dates back to 1956 in an article in the psychoanalytic journal American Imago.

Today, most people understand what you mean when you say you're getting hangry. If you haven't experienced hanger personally, you've probably found yourself the target of a bad attitude from a friend who hasn't eaten recently.

Is hanger just an excuse we use for being irritable when we want something to eat? Or is becoming hangry a real thing? Scientists will tell you that hanger is a real phenomenon and they now understand why people get hangry.

When you eat, your body converts foods into simple sugars, such as glucose, that pass into the bloodstream and get distributed around the body to be used for energy. Your brain, in particular, relies upon glucose to function, and it monitors the level of glucose in your blood carefully.

As time passes since you last ate, the levels of glucose in your blood begin to drop. If glucose levels drop low enough, your brain will release your body's "fight or flight" hormones that seek to increase the amount of glucose in your bloodstream. This process is known as the glucose counter-regulatory response.

Two of the hormones released, adrenaline and cortisol, are stress hormones that get released into the bloodstream in a wide variety of stressful situations. Even though getting hungry might not seem all that stressful to you, a rush of adrenaline can make you irritable.

Stress hormones aren't the only reason we get hangry, though. Scientists have learned that feelings of hunger and anger are also regulated by the same genes. When we get hungry, neurons in the brain secrete a chemical called neuropeptide Y.

Studies have revealed that neuropeptide Y also regulates anger and aggression. Therefore, since the same brain chemical is triggered by both hunger and anger, it's no surprise that we get hangry!

Wonder What's Next?

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