Just eat, guys. (Photo: cartonpiedra/Flickr)

Furious that your spouse forgot to put the sandwich fixings back in the fridge—for, like, the umpteenth time?

Don't get mad. Get eating.

Diabetics understand the dangers of low blood sugar. If recent insulin doses were too high, glucose in a diabetic's blood falls too far below the 100 milligrams-per-deciliter goal, and irritability can set in. Innocuous comments can stab like harsh insults; life's trivialities seem deadly serious. Diabetics use this irrational frustration as a warning sign that soda, fruit juice, or a candy bar is needed—stat.

But diabetics aren't the only ones affected; Anybody can be vulnerable to low blood sugar, especially when hungry. And new research has pinned a share of the blame for domestic quarrels, which can escalate to violent abuse, on hard-to-notice blood sugar imbalances.

The lower a study participant’s blood sugar, the more pins they were likely to stick in the play-sized representation of their lover.

Self-control is not some supernatural state of mind. It takes energy to maintain, and that energy comes from burning glucose. If this energy supply is in short supply, then self-control becomes limited, and it’s harder to regulate emotions and unwelcome impulses.

To test the relationship between blood sugar levels and domestic quarreling, a team of scientists turned to a combination of voodoo and modern medicine. They handed out voodoo dolls and glucometers, which are used by diabetics, to 107 couples. The couples had been married for an average of 12 years. Every evening for three weeks, each partner pricked a doll symbolizing their spouse with as many as 51 pins, with more pricks meaning they felt more marital frustration. They also measured their blood sugar levels.

Sure enough, the lower a study participant’s blood sugar, the more pins they were likely to stick in the play-sized representation of their lover.

Couples who were generally happy with their relationships used fewer pins. (And wives pricked their husbands more often than vice versa, though the relationship wasn’t statistically significant.) After playing with the data to account for such differences, the scientists found a statistically significant negative correlation between blood sugar and spouse frustration levels. The results were posted online Monday by the Proceedings of the National Academy of Scientists ahead of print publication.

The research suggests that couples could cut back on their quarreling by recognizing irrational frustrations and signs of low blood sugar—and snacking it out instead of duking it out.

Glucose meters are available cheap from any drug store (the test strips are the expensive part). Brad Bushman, a professor at The Ohio State University and one of the co-authors of a paper that describes the study, says these meters are the only ways of getting accurate blood sugar measurement. But ordinary signs can also be used to look out for low blood sugar. "How long it’s been since you’ve eaten would be a good sign," he says.

With nearly one in 10 Americans now living with diabetes, there might even be somebody in the family who has a meter that could be used—and who could help explain the early warning signs of low blood sugar.