Binge eating is not due to stress-induced impulsivity

 

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Binge eating is a characteristic symptom of some eating disorders, but stress is not the trigger for such binge eating, according to a study published today in the Journal of Neuroscience.

One of the leading theories about binges is that they are the result of stress, which causes individuals to have self-control difficulties.

However, research led by experts from the University of Cambridge concludes that, contrary to popular belief, people with eating disorders do not lose self-control - which leads them to binge eat - in response to stress.

Research director Margaret Westwater notes that the idea was to find out whether stress affected key brain regions that are important for self-control and, in turn, causes increased food intake.

The study suggests, according to Paul Fletcher, another of the authors, that the relationship between stress and bingeing “is very complicated. It has to do with the environment that surrounds us, our psychological state and the way our body tells us that we are hungry or full "

The researchers counted 22 women with anorexia nervosa, 33 with bulimia nervosa, and 30 without these eating disorders.

For several days, the participants had to perform an inhibitory control task - the ability to stop what was going to be done or is being done - while they were stressed or relaxed and their brain activity was measured.

The task was to press a button to stop a moving bar when it reached a certain point on a screen, but in some trials, the bar stopped prematurely and participants had to avoid pressing the button.

After the task was completed, but when the volunteers could still be expected to be in a state of high stress, they were offered a buffet in a relaxing room, where they were given the option of eating as much or as little as they wanted.

Although theory suggests that patients should have eaten more when stressed, “that's not really what we found. It's clear that when we think about eating behavior in these disorders, we have to take a more nuanced approach, ”adds Westwater.

Stress altered brain activity associated with inhibitory control in the eating disorder groups, but had no effect on task performance, meaning they still had the ability to stop their actions.

These results indicate that self-inhibition is maintained under stress, so the actual mechanism of binge eating is more complex than previously thought.

The researchers found that women with eating disorders generally ate less at the buffet, but the amount of food did not differ between the days they performed the task with or without stress.

The patient groups showed some differences in brain activity when stressed, and that activity differed between women with anorexia and those with bulimia.