Eat before you talk: The sweet reason you're fighting with your partner

Beware hanger! Photography Thinkstock

Warning: Never talk to your partner on an empty stomach.

People are more irritated with their partners when they're hungry, according to a recent study published in the journal Proceedings of the National Academy of Sciences.

Researchers recruited 107 married couples for a 21-day experiment. Every day for those three weeks, participants were asked to stick up to 51 pins into a voodoo doll (let's pause to let that creepy instruction set in) depending on how angry they were with their partner. More pins meant more animosity. They also tested their glucose levels—a measure of their blood sugar, which regulates hunger—twice a day.

The result? People were madder at their mates when their blood glucose levels were low (re: hangry). See, glucose comes from carbohydrates and tells you when you're full. Skimping on food can decrease these levels, causing you to feel hungry and irritable, says Keri Gans, R.D., the author of The Small Change Diet.

The second part of the study further proved this link. In a lab, partners competed against each other to see who could press a button faster after an image appeared on a computer screen. When the person won, they could blast a super-annoying sound into their spouse's ear—like nails on a chalkboard or dentist drills—at any given volume and duration. Once again, the researchers saw an association between hunger and increased aggression toward spouses—but this could apply to any type of relationship.

More: 33 fixes for an empty stomach

So how is glucose connected to your urge to scream at your partner? It all has to do with your noggin. "Even though the brain is only 2 percent of our body weight, it consumes about 20 percent of our calories," says study author Brad Bushman, Ph.D., a professor of communication and psychology at Ohio State University, in a press release. "It is a very demanding organ when it comes to energy."

Essentially, our brains need that energy from glucose to function properly. When those glucose levels drop, you may not be able hold back things you're keeping bottled up, suggests the study. Cue the fiery, hunger-induced rage.

The next time you feel yourself about to blow up when your mate forgets to restock the toilet paper (seriously, how hard is this?!), try to remember the last time you ate. If you're running on an empty stomach and feeling hungry, you might want to take a bite from one of these 8 foods that keep your stomach full before confronting them. And if it isn't the hangry talking, read this to find out how to fight right.