If you've ever blamed a bad mood on low blood sugar, you're onto something.
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If you've ever blamed a bad mood on low blood sugar, you're onto something—being "hangry" (hungry and angry) is a real thing.

Researchers from The Ohio State University and the University of Kentucky put it to the test with married couples, measuring their blood glucose levels daily for 21 days and having them secretly stick pins in a voodoo doll of their spouse each evening (up to 51 pins at a time, depending on how peeved they felt). Those whose glucose levels ranked in the bottom 25% stabbed more than twice as many pins into their "spouse doll" as those in the top 25%.

At the end of the 21 days, the couples came into the lab to play a computer game against each other in separate rooms. The winners could blare an unpleasant noise at their partners, as loudly and for as long as they wanted. Once again, people who had lower average levels of glucose were more aggressive, willing to blast their mate at a louder volume and for a longer time than those with higher levels.

"Glucose gives the brain the energy to exercise control," explains lead study author Brad Bushman, PhD, professor of communications and psychology at Ohio State. When you're hungry, glucose levels drop, making it harder to rein in hostility.

To keep bickering with your partner to a minimum, "the next time there's a sensitive issue to bring up, discuss it over dinner rather than on an empty stomach," Bushman advises. You'll have a happier belly—and maybe even a happier relationship.