OBESITY
The role of psychological factors in obesity
This section explores what obesity is and then examines the role of psychology in under-
standing obesity in terms of its consequences, causes and treatment. The potential role
of psychological factors in obesity is illustrated in Figure 15.1.
WHAT IS OBESITY?
Obesity can be defined in a number of ways, including the use of population means and
in terms of body mass index. Using population means involves exploring mean weights
given a specific population and deciding whether someone is below average weight,
average or above average in terms of percentage overweight. Stunkard (1984) suggested
that obesity should be categorized as either mild (20–40 per cent overweight), moderate
(41–100 per cent overweight) or severe (100 per cent overweight) obesity. This approach
is problematic as it depends on which population is being considered – someone could be
obese in India but not in the USA.
Body mass index (BMI) is calculated using the equation weight (kg)/height (m). This
produces a figure which has been categorized as normal weight (20–24.9) overweight
(grade 1, 25–29.9); clinical obesity (grade 2, 30–39.9); and severe obesity (grade 3, 40+)
(see Figure 15.2). This is the most frequently used definition of obesity. However, it does
not allow for differences in weight between muscle and fat – a bodybuilder would be
defined as obese.
Fig. 15-1 Potential role of psychology in obesityOBESITY AND CORONARY HEART DISEASE 353