Your Personality Could Be Making You Fat

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At any given moment, an estimated 108 million people in the United States are on a diet. But despite the fact that the U.S. weight-loss industry makes roughly $20 billion in revenue each year, people continue to fail for one reason or another. Part of the problem, new research suggests, is that our eating habits are influenced by deep-seated personality traits. Your neuroticism, in other words, could be partially responsible for your love of chocolate and cheese.

For the study, published in the journal Appetite, researchers at the Swiss Federal Institute of Technology sent three questionnaires — one on personality, one on eating habits, and one on food choices — to a random sample of addresses. After excluding subjects who skipped more than 10 percent of the questions, data from nearly a thousand participants (with an average age of 55 years old) was analyzed.

The personality questions were designed to measure what psychologists believe are the five basic dimensions of personality — openness, conscientiousness, extroversion, agreeableness, and neuroticism. The researchers were curious whether, and to what extent, high or low scores on these different traits would correlate with certain eating habits.

We found that a person’s personality does, in fact, determine why he or she eats and what he or she eats,” said Carmen Keller, the study’s lead author. For one thing, “A lack of conscientiousness leads people to eat impulsively and to lose self-control in the face of tempting food situations with palatable and nicely smelling and tasting food,” she explained. In addition, “Neurotic people may eat too much high-caloric food to deal with their negative emotions.”

Extroversion, which, unlike neuroticism or a lack of conscientiousness tends to have mostly positive connotations in society, was also linked to potentially unhealthy eating habits. “A surprising result is that extroverted people eat more due to external reasons — such as a nice smell or the taste of food — and, in turn, they often consume more meat, sweet foods, savory foods, and sugar-sweetened drinks,” explained Keller. “It might be that the higher sociability of extroverted people results in having more meals with other people and, therefore, eating foods that are not healthy.” Indeed, a lot of past research has suggested that social components greatly influence both what people eat and how frequently they exercise, including studies showing that people-pleasers eat more, women mimic each other’s eating behaviors, and finding a walking group can help you become healthier.

Taken together, the results reported by Keller and her team suggest that certain personality characteristics can be seen as “risk factors” for an unhealthy lifestyle. “These findings add to a growing body of evidence showing the importance of the personality traits of neuroticism and conscientiousness for a variety of health-related behaviors, including a healthy diet,” said Tim Bogg, an assistant professor of psychology at Wayne State University, who has studied conscientiousness and health, but who wasn’t involved in this study. “The results show that part of the complicated puzzle of maintaining a healthy diet over the long term is related to our general tendencies for emotion regulation and self-control, not simply how good we are at counting calories or avoiding trans fats.”

In other words, there could be an underrated “know thyself” aspect to successful weight management — understanding how you respond to a stressful day at work, say, or to attending a party where there’s likely to be a lot of food. As Fiona Johnson, a research associate at University College London who also wasn’t affiliated with this study explained, since personality traits are “largely stable over the life course,” understanding the connection between them and eating habits could offer important new opportunities for people to better monitor and control their eating habits. “Overcoming these fundamental tendencies can be very difficult, and identifying ways in which people can boost their capacity to control their eating (eating self-regulation) is the next big challenge in eating research.”

There are limitations to this study — for example, it only sampled Swiss subjects, and did so with self-reported inventories — but it certainly adds some evidence to the common-sense notion that our personalities, which greatly influence how we react to just about everything, also affect what — and how much — to eat. So while there’s more research to be done, those trying to lose weight might want to look into not just calorie-counting apps and healthier foods at the supermarket, but personality inventories, too.