A new study published by the Journal of Personality and Social Psychology says it’s possible.

Three researchers from the US Department of Health and Human Services followed nearly 2,000 people over a 50-year life span and found those who were more impulsive were likely to be about 24 pounds heavier than those who weren’t. They also found that subjects who weren’t terribly friendly may experience  “a greater increase in the Body Mass Index across the adult life span.”