Consistent choice of low-calorie foods in anorexia nervosa (AN) is associated with increased activity in a brain region known to be involved in habitual behavior, reports a study published online in Nature Neuroscience. The findings provide insight into the neural mechanisms underlying AN.

Though AN is a complex illness, one highly stereotyped feature is persistent selection of low-calorie and low-fat food, which can continue even after individuals choose to enter treatment to gain weight. While previous research has examined brain activity in response to passive viewing of food, the mechanisms underlying active food choices are unclear.

Karin Foerde, Joanna Steinglass and colleagues studied 21 patients hospitalized for treatment of AN and 21 healthy control subjects as they made choices between food items that differed in health and taste ratings. To ensure that the choices mattered to the participants, they were given a snack of one of the items they chose following the experiment. The authors found that AN patients consistently choose fewer high-fat items than healthy subjects. Functional magnetic resonance imaging performed while they made these choices indicated that AN patients have increased activity in their dorsal striatum brain region when making choices about what to eat. Furthermore, the authors show that both food choice and the amount of dorsal striatum activity can predict an AN patient’s actual caloric intake in a real-world meal the following day. These findings suggest that altered dorsal striatal activity may play a role in AN, as it does in other maladaptive behaviors.