Having lower blood sugar levels could cause fights between spouses.
Researchers conducted a 21-day study and found blood sugar often predicted how angry spouses would get at each other and whether or not they would lash out aggressively, an Ohio State University news release reported.
The team found those with lower blood sugar levels were often more likely to make loud noises at their spouse with more intensity and for longer than those who did not.
Blood glucose levels can be quickly brought up by eating foods rich in carbs or sugar.
"People can relate to this idea that when they get hungry, they get cranky," Brad Bushman, lead author of the study and professor of communication and psychology at The Ohio State University said in the news release.
The phenomenon is so prevalent that it has been pinned with the slang term "hangry."
"We found that being hangry can affect our behavior in a bad way, even in our most intimate relationships," Bushman said.
The team looked at 107 married people and asked them to rate how much they agreed with certain statements such as "I feel satisfied with our relationship," the news release reported.
The participants were given a voodoo doll meant to represent their spouse and 51 pins; they were asked to stick pins in the doll according to how angry they were at their significant other and record how many they put in. Each participant also had a blood glucose meter that kept track of their levels before breakfast and around bedtime.
"Even those who reported they had good relationships with their spouses were more likely to express anger if their blood glucose levels were lower," Bushman said.
At the end of the study the subjects were asked to come into the laboratory and participate in a competition with their spouse to see who could press a button faster when a red target lit up on a computer screen. The winner was allowed to blast a loud sound into their spouse's headphones; they were also allowed to determine how loud this sound would be and how long it would last.
In reality, the participants were competing with a computer that let them win half the time, as opposed to their partner.
"Within the ethical limits of the lab, we gave these participants a weapon that they could use to blast their spouse with unpleasant noise," Bushman said.
The team found that those who had lower blood sugar tended to blast their spouses with longer and louder noises, even after the researchers controlled for overall relationship satisfaction. Those who had lower blood sugar also stuck more pins in the voodoo doll.
"We found a clear link between aggressive impulses as seen with the dolls and actual aggressive behavior," Bushman said.
The results of this study could be because glucose is "fuel for the brain," which must be sharp in order to control aggressive impulses.
"Even though the brain is only [two] percent of our body weight, it consumes about 20 percent of our calories. It is a very demanding organ when it comes to energy," Bushman said. "It's simple advice but it works: Before you have a difficult conversation with your spouse, make sure you're not hungry."
