This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American
An impulsive personality has long been associated with addiction to alcohol and drugs. Impulsive people are more likely to act rashly when they are feeling bad, for example, making them more likely to use drugs or alcohol when they experience a low. Now, psychologists think impulsivity may lead to another problematic behavior – addictive eating.
People with an impulsive personality were found to be more likely to have a food addiction in a recent study by University of Georgia researchers published in the journal Appetite. People reporting higher levels of food addiction were also more likely to have a higher body mass index (BMI). In other words, impulsive people weren’t necessarily overweight, but impulsivity was associated with a compulsive relationship with food and, as a result, less healthy weight.
The concept of food addiction stems from other parallels between food consumption and addictive drug use. Supporting neurobiological data links tasty food with dopamine release similar to that which occurs when people consume other addictive substances. Food addiction as a whole remains controversial, but researchers at Yale University developed a method for identifying possible food addiction. The measure, known as the Yale Food Addiction Scale, is based on behaviors and characteristics used to diagnose other types of addiction.
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The UGA researchers in the lab of clinical psychologist James MacKillop used the scale to test 233 participants for food addiction. They also measured BMI and then used another scale, the UPPS-P Impulsive Behavior Scale, to gauge how impulsive individuals were.
Impulsivity actually includes multiple personality traits. Personality traits vary among people, but they tend to be stable over time in individuals.
Two traits involved in impulsivity, known as negative urgency and lack of perseverance, were especially related to food addiction and high BMI in the UGA study.
Negative urgency refers to the tendency to behave rashly when experiencing negative emotions. For some, that means drinking alcohol or doing drugs. For others, that might mean eating to get rid of a bad mood – a situation that could lead to weight gain.
Lack of perseverance is difficulty following through with hard or boring tasks. People with high levels of this aspect of impulsivity might have a hard time following through with attempts to change addictive eating behaviors, which could also cause an overweight or obese BMI.
Impulsivity has been shown to be associated with weight gain in previous studies. Overweight or obese children were found to be more impulsive than healthy children, according to one 2013 review. One 2010 study found overweight and obese women had higher levels of negative urgency and lack of perseverance.
Impulsivity might be one reason some people eat in an addictive way despite societal motivation against weight gain, according to Ashley Gearhardt, a clinical psychologist who helped develop the Yale Food Addiction Scale.
“One of the key hallmarks of addiction is impulsivity,” said Gearhardt, who is now an assistant professor at the University of Michigan. “We were theorizing that if food addiction is really a thing, then our measure [the Yale Food Addiction Scale] should be related to impulsive action.”
Given the parallels between addictive eating and other addictive behaviors, MacKillop thinks therapies used to treat other addictive behaviors could help people eat in a healthy way.
Mackillop’s group uses an in-house bar lab to provide self-control training to people with alcohol addiction. The drinker spends time in the bar lab, where craving is induced but not fulfilled. A person might be poured their favorite drink and asked to lift it to their nose but not drink, for example. MacKillop found that over time people became less sensitive to these alcohol cues and were able to reduce their drinking.
“Most of the programs for weight loss at this point focus on the most obvious things, which are clearly diet and exercise,” MacKillop said. “It seems like craving management or managing acute desires to eat would have a natural fit within the domain of skills a person would need to eat healthily.”