Ask the Doctors

Dear Doctor: My 16-year-old daughter is normally very sweet and accommodating. But when she's hungry, she becomes a completely different person. I think she can control her mood when she's hungry; she insists she can't. Who's right?

Dear Reader: Not only is the hunger-related crankiness you're describing a real thing, it's prevalent enough to have recently earned an entry in the Merriam-Webster dictionary. According to the official definition, your daughter is "hangry." As the dictionary puts it, hangry is "a clever portmanteau of hungry and angry, and an adjective that describes being irritable due to hunger." But why?

When it's been too long between meals, there's more going on than just that hollow feeling and a stomach rumble. The real action takes place in the brain, which like the rest of the body, uses glucose to function. In fact, the nerve cells of the brain, known as neurons, are so plentiful and active that they use half of all of the glucose we take in each day. Wait too long between meals, and blood glucose levels drop. When this happens, the brain, which plays a role in virtually every vital function that keeps us alive, lets us know. And not in a polite, "Ahem, I'm a bit peckish, can we maybe eat sometime soon?" kind of way. With that blood sugar drop, the brain sets in motion a cascade of biological processes that basically shout: FOOD! NOW! I MEAN IT!

Specifically, when blood sugar drops to levels the brain finds inadequate, it triggers the release of cortisol and epinephrine. Known as counterregulatory hormones, they act against the effects of insulin and raise levels of blood glucose. Also involved in the complex hunger response is something called neuropeptide Y, which contributes to the physical sensation of emptiness.

In addition, cortisol and epinephrine are so-called stress hormones and are associated with increased levels of aggression. So is neuropeptide Y. So as blood sugar levels drop, the biochemicals released to increase the fuel available to the brain are also paving the way for us to feel stressed and angry. Some researchers theorize that this is no accident. While neuropeptide Y is busy making us feel empty, cortisol and epinephrine are making sure that nothing will come between us and finding that next meal that the brain so desperately needs.

In experiments exploring the hunger-anger nexus, researchers from the University of North Carolina at Chapel Hill found a connection between hunger and negative emotions. Participants looked at images that were either positive, negative or neutral. They were then shown a Chinese pictogram. Those who were hungriest, and who had previously viewed a negative image, were the most likely to feel negatively toward the pictogram. Those who reported lower levels of hunger didn't have the same level of negativity. Still, another experiment bolstered your "you can control your hanger" point of view. When participants were asked to be aware of their emotions, the hungry ones experienced less hanger.

So you and your daughter are both right. Hanger is real, and for some people, it can be controlled.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095. Owing to the volume of mail, personal replies cannot be provided.)

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