A

ustralia isnow ranked as one of the fattest
nations in the world, with 14 million Australians
currently overweight or obese. By 2025 it is
predicted that about 80% of Australians will
be overweight or obese (tinyurl.com/z8apzug).
Due to the increasing prevalence of diseases associated with
obesity, it is now the biggest threat to public health in Australia.
It has overtaken smoking as the leading cause of illness and
premature death. To put this into perspective, the World
Health Organisation estimates that overweight and obesity are
responsible for about 45% of diabetes, 23% of heart disease
and7–41% of certain types of cancer globally.
One ofthe major problems is that obesity is very resistant to
behavioural interventions such as diet and exercise.Ofthe indi-
viduals who manage to lose weight, only about 5% maintain
that weight loss– andthis only with a high degree of self-moni-
toring.
People who become obese no longer regulate their appetite
or metabolism in the same way as an individual who has never
been obese. While drug therapies have targeted the central

nervous system to control appetite, they have had limited effect

or unacceptable side-effects.

Currently the most effective treatment for obesity is bariatric

surgery.However, surgery is not a practical solution forthe

increasing number of obese people due to the high costs and asso-

ciated mortality rates. Bariatric surgery is reserved for severely

obese individuals with a body mass index (BMI) greater than

40, or individuals with a BMI greater than 35 but with obesity-

related comorbidities where drug therapies or lifestyle changes,

such as diet and exercise, have been unsuccessful.

If we can develop safe and relatively inexpensive medica-

tions that mimic the effect of bariatric surgery then perhaps

we can prevent the onset of severe obesity and the co-morbidi-

ties associated with it. With this in mind there is renewed

interest in the role of the gastrointestinal tract in appetite regu-

lation, energy intake and blood glucose control.

The stomach and small intestine play complementary but

distinct roles in appetite regulation. In the stomach wall there

are vagal afferent nerves that detect stretching as food enters and

gradually ills the stomach. The activated nerves signal to the

MAY 2016|| 21

The Stomach as a

Target for Obesity

AMANDA PAGE

Obesity permanently changes the way our body processes gastrointestinal signals about

satiety. While appetite suppressants have had limited success, the identification of an

appetite-regulating nerve channel offers a new approach to keeping weight off.

MartesiaBezuidenhout/adobe