NEDA TOOLKIT for Parents
Reward In eating disorders, scientists have identified problems
not only with the physical sensations of hunger and
fullness, but also with how rewarding food is. If an
animal doesn’t eat enough, it will die, so necessities
like eating are generally quite pleasurable to ensure
that we stay alive. This pleasure helps reinforce the
behaviors, thoughts, and memories that lead to
eating. Alternately, the brain usually perceives hunger
as being uncomfortable to motivate us to go eat
something. Research has shown us that the brain’s
reward pathways are altered in individuals with eating
disorders, making them more or less able to perceive
and respond to pleasurable things.
Normally, when we are hungry, food is more rewarding
than when we are full (Bragulat et al., 2010), as
evidenced by the increased release of dopamine in the
nucleus accumbens, which is known to play a role in
pleasure, reward, addiction and fear (Avena, Rada, &
Hoebel, 2008). Given that food restriction frequently
accompanies binge eating behavior (Stice et al., 2000),
the binge becomes even more rewarding in these
individuals than the normal satiation of hunger. The
post-binge guilt leads to further food restriction, which
serves to maintain the high reward of binge eating
(Carr, 2011).
Neuroimaging studies in women with bulimia revealed
that their brain’s reward pathways are significantly
more active than in healthy controls when they viewed
pictures of food (Brooks et al., 2011). Women with the
binge/purge type of anorexia also showed significantly
higher reward sensitivity (Harrison et al., 2010).
Despite increased awareness and diagnosis of binge
eating in males, the disorder is still significantly more
common in females. Some researchers believe that
female sex hormones may help increase reward
sensitivity (Klump et al., 2013). Scientists are currently
testing this idea.
In bulimia, purging appears to be rewarding as well.
One study found a significant association between
higher reward sensitivity and frequency of purging in
women with bulimia (Farmer, Nash, & Field, 2001). One
potential explanation for this is that purging decreases
the amount of acetylcholine in the brain, high levels
of which have been found to be unpleasant (Avena &
Bocarsly, 2012).
This altered reward system in individuals who binge
eat is evident in areas besides food. Studies have found
that high school students who reported regular binge
eating were much more likely to report use of drugs,
alcohol, or tobacco than non-binge eaters. Those
students who also engaged in compensatory behaviors
like fasting or purging were most likely to use these
substances (Ross & Ivis, 1999).
In anorexia, a large number of studies have instead
found significantly decreased reward sensitivity, as well
as an over-response to punishment (Harrison et al.,
2010). Neuroimaging studies also revealed unusually
high levels of cognitive processing when individuals
with anorexia viewed images of food (Cowdrey et al.,
2011). Because food is less rewarding and appears
to be associated with fear and punishment, people
with anorexia tend to place a higher emphasis on the
long-term goal of weight loss and maintaining anorexic
behaviors rather than food’s more immediate rewards
(Kaye et al., 2013). They also tend to report high levels
of ascetic behaviors (Keating et al., 2012).
These differences in reward processing across the
eating disorder spectrum appear to persist after
recovery (Wagner et al., 2010; Wagner et al., 2007).
Because of this, some researchers believe that these
results may indicate that these traits exist before
disease onset and are corroborated with reports of
childhood behaviors (Anderluh et al., 2003). Still, it
also remains possible that these post-recovery traits
are scars from the illness rather than pre-illness risk
factors. In some religious and cultural traditions, the denial of
pleasure is typically seen as a good thing. Thus it may
seem that individuals with anorexia have a “better”
way of managing reward. This isn’t true. When you’re
truly physically hungry, it’s good to focus on the
immediate rewards of eating. Difficulties in shifting
focus from the potential benefits of long-term goals
to the more immediate benefits of feeding a starving
body and pursuing recovery can keep people stuck in
anorexia nervosa for years.
References: Anderluh, M. B., Tchanturia, K., Rabe-Hesketh, S., & Treasure,
J. (2003). Childhood obsessive-compulsive personality traits in
adult women with eating disorders: defining a broader eating
disorder phenotype. American Journal of Psychiatry, 160(2),
242-247. doi:10.1176/appi.ajp.160.2.242
Page | 72