Lower levels of blood sugar may make married people angrier at their spouses and even more likely to lash out aggressively, suggest researchers.
In a 21-day study, researchers found that levels of blood glucose in married people, measured each night, predicted how angry they would be with their spouse that evening.
At the end of the 21 days, people who had generally lower levels of glucose were willing to blast their spouses with unpleasant noises at a higher volume and for a longer time than those who had higher glucose levels.
Blood glucose levels can be brought up most quickly by eating carbohydrates or sugary foods.
The study lead by Brad Bushman, lead author of the study and professor of communication and psychology at The Ohio State University, involved 107 married couples. The study started with the couples completing a relationship satisfaction measure, which asked each spouse how much they agreed with statements like "I feel satisfied with our relationship."
All participants were given a voodoo doll that they were told represented their spouse, along with 51 pins. At the end of each day, for 21 consecutive days, the participants inserted 0 to 51 pins in the doll, depending on how angry they were with their spouse. They did this alone, without their spouses being present, and recorded the number of pins they stuck in the doll.
Each person also used a blood glucose meter to measure glucose levels before breakfast and every evening before bed for the 21 days.
The result: The lower the participants' evening blood glucose levels, the more pins they stuck in the doll representing their spouse.
The study has been published online in the Proceedings of the National Academy of Sciences.