Abstract:
Obesity is defined as an excess accumulation of body fat
associated with increased fat cell size and number. Obesity is a
common and serious medical problem worldwide, especially in
industrial countries, but the prevalence of obesity is also
increasing in developing countries such as South Africa.1 One
of the key factors accounting for this may be increased
urbanisation.2 The movement of populations from rural to
urban areas is associated with major changes in lifestyle,
particularly the increased availability of calorie-dense foods
and drinks. Although obesity is associated with social stigma
in Western countries, public opinion of obesity and overweight
in the Middle East and Africa is different, being associated
more with health and wealth.
Obesity occurs when energy intake is greater than energy
expenditure. The surplus energy will be stored as fat in the
adipose tissue. In the last decade there has been a plethora of
data relating to the fact that adipose cells are not just a storage
depot for excess calories; rather they are metabolically active
tissue. Leptin, and more recently a number of additional
hormones, growth factors and cytokines,3 have been reported
to be secreted by adipocytes and to have paracrine as well as
endocrine effects on a variety of target tissues. It is also known
that the different fat depots in the body have different
metabolic activities and this may relate to their differential
effects on insulin sensitivity.
