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How do Anorexics Control their Appetite?

By Quinn Dombrowski from Chicago, USA (Day 355: Happiness is Double Fries) [CC BY-SA 2.0 (http://creativecommons.org/licenses/by

Many individuals, regardless of how much they weigh, will avoid fat laden foods and rich, sweet desserts. However, despite one’s best intentions, when the moment of truth comes, that brownie or chocolate cake is just too irresistible and all self-control vanishes.

This behavior is entirely normal, because hunger increases the intensity of a food reward. Yet, for those with anorexia nervosa, despite their state of starvation and hunger, they can still ignore these tasty foods.

Study

A new study was done by Dr. Christina Wierenga, Dr. Walter Kaye and other colleagues, the results were posted in Biological Psychiatry. It was established that certain brain mechanisms could contribute to the disturbed eating patterns of anorexics.

The team examined reward responding in relation to how hungry or satiated 23 women were while in recovery from anorexia nervosa and 17 women without a history of eating disorders. Women with active anorexia were not studied in order to reduce the potential confusion related to malnourishment.
The healthy women in the study, when in a state of hunger, showed an increase in activity in the portion of the brain that motivates reward seeking behavior, but when women recovered from anorexia it didn’t. The women in recovery also exhibited an increase in activation of cognitive control circuitry regardless of their current metabolic state.

Hence, the women in this study who had recovered from anorexia nervosa showed two related patterns of changes in brain circuit function that may directly contribute to their capacity to avoid food.

Findings

Firstly, hunger doesn’t increase the engagement of the reward and motivation portions of the human brain. This may protect those with anorexia from hunger-related urges. Secondly, they showed an increase in the activation of executive “self-control” circuits of the brain, perhaps allowing them to be more effective at resisting the temptation of food.

The study supports the idea that anorexia is a neurobiological-based disorder. Medical researchers have long been stumped by the fact people with anorexia nervosa can restrict their intake of food, even when starving. Hunger is a motivating factor and it makes rewards seem a lot more tempting. The findings of this study suggest that people with anorexia nervosa, even after they have recovered, are less sensitive to the reward and motivational drive of hunger. It is apparent that hunger does not motivate an anorexic to eat.

The study offers new insight into the brain of a person with anorexia, which researchers are using to guide treatment efforts and to reduce the stigma associated with this horrible and deadly disorder.

Conclusion

Anorexia nervosa is a devastating and highly destructive disease and the study helps put a new light on the brain mechanisms that could enable people to starve themselves. In having these mechanisms identified, it could provide better treatment options in the future.