Mind Your Body: Weighty Personalities

Your personality influences many life experiences. Now comes word that it might be making you fat...then thin, then fat again.

The Big Five measures of personality are associated with different patterns of weight gain, according to researchers at the National Institute on Aging. A team led by neuroscientist Angelina Sutin looked at data tracking 2,000 people for more than 50 years. "We know personality traits are associated with other health indicators, like smoking," Sutin says. "We wanted to see if they're also associated with weight." Here's what they uncovered.

Haste Makes Waist

People who score in the top 10 percent on impulsiveness weigh 22 pounds more than those in the bottom 10 percent, on average. Impulsive people have trouble planning ahead and resisting temptation. "An impulsive person intends to go to the gym, but then something pops up and they follow that impulse instead," explains Sutin.

Another predictor of having a large waistline is low agreeableness, a.k.a. antagonism. Antagonistic people tend to have stronger physiologic responses to stress, and other studies have associated higher levels of the stress hormone cortisol with weight gain. Could packing on the pounds make you surly? Since temperament is stable over time, Sutin believes personality influences weight, not vice versa.

Sad Cycle

Some people yo-yo between losing and regaining weight. Sutin's study found that this cyclical pattern often occurs in people both high in neuroticism and low in conscientiousness. Two dispositional elements that lead to negative emotions, depression and impulsiveness, were especially associated with weight fluctuations.

Depressed people frequently experience changes in appetite, which may explain some of the seesaw effect. And a 2009 study showed that when impulsive people restrict their food intake, they're even more likely to overeat when faced with temptation than impulsive people who aren't dieting. Coupled with the lack of self-discipline associated with low conscientiousness, these traits can be a recipe for a lifetime of weight fluctuations.

Strictly Slender

Highly conscientious people have the easiest time maintaining a healthy BMI. They tend to be thin and keep the same weight over time, according to the study. That's because they have more self-control and are often more conscious of their weight.

Slim Simply

Impulsive, antagonistic people aren't doomed to a lifetime of fighting the scale. Weight-loss programs should be designed around personality types, Sutin says. "Buying healthful groceries, having set meal times, and planning ahead help with weight management," she says, but these are the kind of tasks impulsive people struggle with. "Interventions that assist with menu planning—say, online meal planners—could help impulsive people manage their weight."