Irrespective of the arguments presented above, there are limitations to the prescription of intensive exercise for overfat people, which make high intensity exercise prescription for fat loss both impractical and irresponsible. Because of the inverse association between body fat and cardiovascular fitness, high intensity activity in people with low cardiovascular efficiency may be potentially dangerous, even fatal. Strenuous exercise is uncomfortable and it may result in overfat people becoming totally disenchanted with physical activity as a fat loss technique. It may also help explain the failure of the fitness industry to attract significant numbers of the almost 1 in 2 people requiring weight control services in Western countries.
A further argument given for high intensity activity is that, given a set period of available time, more vigorous activity provides more ‘bang for the buck’ in terms of body fat utilisation. If the time is extensive enough to allow for adequate fat utilisation, however, a fat unfit person is unlikely to be able to complete an exercise session at a high (e.g. 70-80 per cent V02) level of intensity. Even if it were possible, it is a diminishing effectiveness of response in relation to fat utilisation with longer duration which would defeat the purpose of the exercise. Because exercise at such a high intensity may also be uncomfortable for such a person, he or she is not likely to want to do it on a regular basis, as is necessary for optimal fat loss.
*144\186\4*
The prevalence of overfatness in the modem world is related to Westernisation. With industrialisation comes ease of accessibility to foods, especially processed and fatty foods. Some industrialised countries have a higher level of overall fatness than others, with Eastern Europeans currently topping the charts. The United States is at the top of the fatness tree amongst Western nations, but Australia, New Zealand and the United Kingdom are not far behind.
Fatness is even more prevalent in certain ethnic groups such as Australian Aborigines, Pacific Islanders and American Indians. It has been suggested that these people may have a genetic makeup (‘thrifty genotype’) which enables them to store more fat during times of ‘feast’ and/or use less energy during times of famine’. It is proposed that the harsh conditions and inconsistent food supply would have preferentially selected those people with the ‘thrifty genotype’ by giving them a survival advantage. To date, no genes have been found which endower a major propensity for fat storage and it seems unlikely that the genetic predisposition to obesity will be pinpointed to one or a few genes. Nor have any genetic markers for obesity been found in ethnic groups with high rates of obesity.
What is well known is that ethnic groups like the Aboriginal people suffer from a high rate of obesity-related diseases such as adult onset diabetes. In Nauru, for example, where super phosphate has made the population rich and the island poor, Professor Paul Zimmett of the WHO has estimated that around 20-30 per cent of the adult population have diabetes. The Pima Indians of Arizona, who have been acculturated to the modem American diet, have extreme levels of obesity and the highest rate of diabetes in the world at 50 per cent of the adult population (compared to around 3 per cent in the White community).
This picture of an obese Western world might suggest that people are indifferent to their growing corpulence. Yet the figures show otherwise. Surveys carried out in the US suggest that at least 25 per cent of men and 40 per cent of women are trying to lose weight at any one time. Over the course of a year, the number of people who attempt to lose weight at least once rises to around 40 per cent for men and 80 per cent for women. The average man wants to lose 22kg to weigh 80kg and the average woman 22.5kg to weigh 60kg. Only 27 per cent of those who see themselves as overweight admit to not currently trying to slim. Perhaps as expected, the majority are using diet as the main method—76 per cent of men and 85 per cent of women. Around 60 per cent of both men and women use increased physical activity as a means of reducing weight.
*5\186\4*
