Biology Reference
In-Depth Information
13- and 15-year-old students. The country with the highest prevalence of
overweight or obesity was the United States for 11- (boys: 25%, girls:
33%), 13- (boys: 27%, girls: 35%), and 15- (boys: 28%, girls: 32%) year-
old students. The HBSC survey also reported that in North America and
Western Europe, higher levels of overweight and obesity were reported
in families with lower income and among boys.
In summary, these findings clearly indicate that this obesity epidemic is
no longer restricted only to the developed western nations but is also grow-
ing rapidly in developing countries in the tropics.
2.5. Obesity studies conducted in the tropics
In addition to the GSHS, we have compiled and reviewed the data on over-
weight and obesity prevalence from nationally representative surveys that are
available from several tropical countries. The findings are summarized in
Table 2.1
. Similar to the global data (GSHS), the findings summarized from
local national surveys clearly indicate that there is a rise in the overweight and
obesity rate among adolescents in most tropical countries, including less-
developed regions, such as Vietnam and Guatemala (particularly among urban
populations). Even in Brazil, the prevalence of overweight adolescents was
shown to have quadrupled over a period of 28 years (from 1975 to 2003).
It must be noted, however, that different cut-off points were used by
these countries in classifying the body weight status of adolescents, and
therefore the results are not directly comparable. Nevertheless, current evi-
dence clearly showed that overweight and obesity have emerged as serious
health problems that must be addressed among children and adolescents liv-
ing in the tropics, along with addressing the undernutrition problem that still
exists in many of these developing countries (
Caulfield, de Onis, Bl¨ ssner, &
Black, 2004
)
.
3. PHYSICAL ACTIVITY IN THE TROPICS
3.1. Physical activity
PA has been defined as a behavior involving bodily movement produced by
skeletal muscles that results in an increased EE (
Caspersen, Powell, &
Christenson, 1985
)
. According to the basic concept of human EE, PA
accounts for the second largest part of daily EE and is viewed as the
most variable component compared to basal metabolic rate (BMR) and
thermogenesis (
Food & Agriculture Organization (FAO), 2004
)
. Hence,
