In a small study, US researchers found decreased blood flow in bulimic women to a part of the brain involved in self-critical thinking.
This supports the idea they may be using food to avoid dwelling on negative thoughts about themselves.
Bulimia usually leads to binge-eating and then purging, through vomiting.
It is an eating disorder and a mental health condition that means people have an abnormal attitude to food and body image.
Psychologists have long thought that binge-eating is triggered by stress and gives women with bulimia a way of focusing on food, instead of being critical of themselves.
This is the first study to look at what happens in their brains.
Writing in the Journal of Abnormal Psychology, Washington researchers scanned the brains of 20 women – 10 with bulimia and 10 without – while carrying out experiments.
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