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Wednesday, December 26, 2007

IS OBESITY PREVENTABLE?

The pandemic of overweight and obesity is now so advanced and so widespread that few regions of the world (with the possible exception of parts of sub Saharan Africa) appear to have escaped the effects of this major public health problem. Previous chapters have highlighted the strong biological influences that contribute to the creation and maintenance of a positive energy balance in humans; current attempts to abate the rapid increase in body weight at both an individual and a community level have been less than inspiring. This has led some people to question whether it is possible to prevent continued increases in population body weight.
Despite these concerns about the effectiveness of current obesity prevention approaches, there is indirect evidence from a range of sources that supports the view that prevention is not only feasible, but offers the only solution to controlling the worldwide epidemic of obesity. Bouchard (4) indicates that the heritability of obesity and body fat stores is only moderate and that recent increases in obesity rates have occurred at a rate too fast to be explained by changes in the frequency of obesity genes or susceptibility alleles. He concludes that the increase in obesity prevalence can only be due to the fact that a greater number of children and adults are in positive energy balance and that it should be possible to attend to this through influencing diet and physical activity patterns. This view is supported by studies of monozygotic (MZ) twins discordant for body mass index (BMI) which have shown that mean body weight can vary between the overweight and lean sibling by up to 16 kg in men and 19 kg in women, even though they have exactly the same genotype.
While the obesity epidemic appears to be affecting all regions of the world, there are some countries that appear to less affected than others. In the Netherlands, the rates of obesity for both men and women are only half of that experienced in the United Kingdom or neighboring Germany and are increasing at a much slower rate. In Brazil the prevalence of obesity within
upper-income, urban women has actually decreased in recent times, although men continue to put on weight at a rapid rate . In addition, while rates of obesity continue to climb in Finland, men from higher education grades have shown only a marginal increase.
Attempts to reduce the rising rates of obesity and poor physical fitness in Singapore appear to have been successful, at least in the short term. Intensive programs of physical training and influence over dietary intake resulted in a significant reduction in the number of schoolchildren being classified as overweight between 1992 and 1995 . Studies of young men inducted into the Singapore army also showed improvements in mean BMI during their periods of service, which unfortunately are reversed when they are released from the military.