According to a 2014 study published in PNAS, low blood sugar levels caused by hunger can make people have less self-control and say hurtful things to their partners.
The study employed 107 couples for 21 days (via The Columbus Dispatch). Each participant was given a voodoo doll (which they were told to imagine were their significant other) and 51 pins which they were asked to literally “pin” to the dolls as a way to vent their frustrations. The participants’ blood sugar levels were monitored twice daily. They found that the lower the blood sugar levels, the more the number of pins on the voodoo doll. Twice as many pins were pushed into the dolls by participants with low glucose levels than those with higher numbers.
The study also used a different test where participants were allowed to play blaring music into the ears of their partners who were wearing headphones as a way to unleash their anger, per CBS News. Again the lower blood glucose levels synced up with the louder and longer blasts. It comes as no surprise that we need to fuel our bodies with food, and even though our brain is smaller in comparison to the rest of our body, it consumes 20% of the calories we ingest, lead author of the study and Ohio State University psychology researcher, Brad Bushman shared with CBS News.