The Psychology of Eating: From Healthy to Disordered Behavior

8

Obesity

One problem related to eating behavior is obesity. This chapter first exam-
ines the prevalence and definition of obesity. It then describes the possible
physical and psychological consequences of obesity and focuses on theories
which have been developed to explain its etiology. In particular it describes
physiological theories including the role of genetics, metabolic rate, fat cells,
and the impact of genes on appetite. It then explores behavioral theories,
with a focus on the role of physical activity and the impact of diet.
This chapter covers the following:

• What is obesity?


• How common is obesity?


• What are the consequences of obesity?


• What are the causes of obesity?


• Problems with obesity research

What Is Obesity?

There are many definitions of obesity which are used by different
researchers and clinicians in different countries. The most commonly used
definitions include the following.

Population means

Using population means to define obesity involves exploring mean
weights within a specific population and deciding whether someone is below
average weight, average, or above average in terms of percentage overweight
for a given height. This approach is problematic as it depends on which