What your personality says about whether you'll gain weight

Are you naturally grumpy or happy, sociable or introverted, optimistic or cynical? Your answer can help predict whether you'll become overweight in your lifetime, according to a new study from the American Psychological Association that pinpointed who was most likely to gain weight or stay slim.

The research is the first to look for a connection between temperament and BMI, and it found that personality type was a good predictor of weight. The researchers drew their conclusions by pulling data from the Baltimore Longitudinal Study of Aging, which includes 50 percent women, and tracks participants over more than 50 years. They looked at the Big Five traits — openness, conscientiousness, extraversion, agreeableness and neuroticism — and subcategories of each.

The most important factor was impulsivity: Participants who were in the top 10 percent of impulsivity weighed 22 pounds more, on average, than those in the bottom 10 percent.

What else was connected to weight fluctuations? Enjoying taking risks and being more neurotic, extroverted, and less agreeable, especially in cynical, competitive or aggressive people. And the trait that was connected to maintaining a constant weight: conscientiousness.

Not sure where you fit in? Check out the Big Five test and score yourself.