Being impulsive may make you one helluva fun and spontaneous friend, but that no-holds-barred personality trait can backfire when it comes to eating habits, causing you to pack on the pounds.New research published in the Journal of Personality and Social Psychology shows that your personality plays a key role when it comes to your weight, particularly if you’re impulsive. Although most people gain weight gradually as they age, the researchers found greater weight gain in impulsive people, risk-takers and those who are antagonistic—especially if they’re cynical, competitive and aggressive.“Impulsiveness refers to the inability to control cravings and urges,” says study author Angelina Sutin, Ph.D. “Desires—for food, cigarettes, possessions—are perceived as being so strong that the individual cannot resist them, although he or she may later regret the behavior.”So it’s no surprise they have trouble fighting their comfort food cravings or saying no to seconds. “Impulsive people are the ones who have the most trouble resisting the tempting brownie or can’t stop themselves from having just one more serving of a great meal,” explains Art Markman, Ph.D., YouBeauty Psychology Advisor. “They are also likely to have some negative moods that they might fight by eating.” What’s more, previous research has shown that people who binge eat and drink alcohol—both of which add up to extra calories—tend to be impulsive.MORE: The Science of Comfort Food“People who scored low on impulse control have trouble resisting their cravings and urges,” says Sutin. “As such, individuals with this trait may have difficulty regulating their food intake and tend to overeat. This is due to both a lack of control and a strategy to regulate emotions. Over time, these individuals may have a hard time controlling their weight.”The powerful influence of personality may explain why joining a gym and buying the latest diet fad book doesn’t always help people shed excess pounds. Impulsive people may be better off with nutritional counseling or behavioral modification strategies (in addition to hitting the gym regularly) to help them learn to curb their impulsivity and find healthier ways to cope with negative emotions than downing a pint of ice cream.For example, for people who are highly impulsive, not keeping snack foods around the house is a good move since it prevents uncontrollable, impulsive eating. Says Markman, “recognize that your natural reaction is going to be to do the thing that feels best in the moment”—and sometimes that can mean reaching for an apple pie instead of an apple. By having healthy foods on hand, you’re more likely to make wiser, waistline-friendly choices.QUIZ: What’s Your Eating Personality?