Emotions, stress, and appetite are all controlled by the same part of the brain, leading researchers to explore how different personality traits and habits can contribute to obesity. "If we can understand how personality is contributing to weight gain," says National Institute on Aging researcher Angelina R. Sutin, "we can develop interventions to help people deal with it." In a study of nearly 2,000 Baltimore residents that compared body mass index and personality traits, researchers found that neuroticism, impulsivity, night owls, stress junkies, habitual multitaskers, givers, and perfectionists are more prone to weight gain. Those identified as neurotic tend to experience negative emotions easily, are less conscientious, organized, and disciplined, and were most likely to be overweight and obese. Those who scored in the top 10 percent of the impulsivity scale were an average 24 pounds heavier than those who scored in the lowest 10 percent. Sleep deprivation common among night owls interferes with the production of leptin, the hormone that regulates appetite, and ghrelin, the hormone that stimulates appetite. By getting up early, limiting caffeine after noon, avoiding light and screens in the evening, and not eating after 9:00 p.m., night owls can reset their internal clocks. Stress junkies who thrive on deadlines and competition have chronically high levels of adrenaline and cortisol, stress hormones associated with belly fat. Exercise can help burn off excess cortisol, and finding non-food rewards for hard work can balance stress. Multitaskers who eat mindlessly while engaged in other activities often eat more than they realize. Keeping a food journal and sitting down to eat meals helps increase awareness and decrease consumption. Givers who put other people`s needs ahead of their own may seek comfort in food, but since it is a poor substitute for emotional closeness, givers may eat more and more trying to fill that need. "You don`t have to change your whole personality," says Beck Institute for Cognitive Behavior Therapy president Judith S. Beck. "You just need to change your thinking, which allows you to change your behavior."