Welcome back. This is Part 2 of our talk around the hedonic aspects of eating.
Now, there may be particular types of people for whom the addictive behaviours,
and eating behaviours may be particularly more
homogeneous and maybe some of the reasons why our differences in obesity
are so marked between the different studies,
because we are with a very heterogeneous cause.
Binge eating disorder may be regarded as
perhaps a more homogeneous cause of obesity and a more homogeneous eating behaviour.
In bariatric clinics, it accounts for about a quarter to maybe a third of patients.
It's characterised by situations in which people will eat a large amount of food,
maybe the amount they would normally eat in a whole day in
a relatively short period of time with a subjective feeling of loss of control,
with no associated purging such as vomiting as is seen in bulimia nervosa or use of
laxatives or excessive exercise.
There are also certain frequencies which need to be done in order to meet the diagnosis.
The episodes are associated with eating very rapidly,
and people feeling quite uncomfortable,
even eating when they're not hungry,
often eating alone or in secret and feelings of disgust and guilt afterwards.
It's exacerbated by emotional stress and also by skipping meals,
suggesting that the homeostatic changes may also impact on that.
There have been some brain imaging studies comparing
people with binge eating and non-binge eating.
Binge-eating may be associated with normal weight.
But in these studies, they compare people
who are overweight with or without binge eating.
As you can see in the picture,
people who had binge eating had greater activation within the brain,
including within the orbitofrontal cortex.
Binge-eating is associated with worse outcomes
in lifestyle interventions such as the Look AHEAD study recently from the States.
Bariatric surgery is not a cure for these behaviours,
and psychological support is needed.
If people do persist to having some of these abnormal eating behaviours after surgery,
they necessarily don't do as well in terms of losing weight.