Western medicine has a long history of blaming the victims of illness for their illness, attributing moral and character defects to the ill – eg, those suffering from cholera (before the mid 19th century), from physical addictions (until the mid 20th century), and from stomach ulcers (until the discovery of Helicobacter Pylori in 1982). The most recent morality campaign waged by the medical profession has been against the obese, who are assumed by many medical practitioners to be lazy, weak-willed, or worse. The medical professions urge the over-weight to diet and to exercise, and they even restrict treatment in some cases to people who are not obese. Never mind that the scientific evidence for the relationship between regular exercise and appetite is weak, and suggests in any case that the former increases the latter: so that, if anything, more exercise is likely to lead to increased weight, not to reduce it.
Now, science tells us that appetite – and hence obesity – may also be a function of one’s genes, as this article in tomorrow’s SMH reports.
SOME of the children were so fat they had been listed on the British social services ”at risk” register because it was assumed their parents were abusing them with deliberate overfeeding.
”In one case, one of the children had been taken into care,” said Stephen O’Rahilly, a world expert on the genetics of obesity at the University of Cambridge.
But then his research team discovered the problem. The obese children had a section of DNA missing in their genetic code – a fault that produced a very strong drive to eat.
”They are very hungry children and very hard to keep healthy,” said Professor O’Rahilly, who will give a public lecture at the Garvan Institute in Sydney on Tuesday titled My Genes Made me Eat That.
The research, published this week in the journal Nature, is the latest discovery in understanding better why some people are more likely than others to become overweight and obese.
A food-on-tap environment had contributed to the obesity epidemic but telling people to eat less and exercise more would not solve it, he said, when about 70 per cent of body size and shape was determined by genetic inheritance.
”There is a general assumption that staying thin means you are a more clever or morally superior person and that you’ve resisted this obesagenic influence consciously.”
But it took much more self-control for an obese person to lose weight and maintain it than for a genetically lean person, he said.
Professor O’Rahilly’s team found the first genetic fault linked to childhood obesity more than a decade ago and showed that giving children the protein they lacked, leptin, led to weight loss.
While big genetic mistakes such as this were responsible for a small number of cases, for most overweight and obese people it was the result of a combination of many genetic variations with small effects, he said.
More than 60 of these variations have been identified and most appear to be active in the brain and to influence hunger, appetite and and satiety.
”Some of these genes will be affecting your weight by only a pound,” Professor O’Rahilly said.
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Professor O’Rahilly said obesity should be regarded as a ”heritable neuro-behavioural disorder” and he hoped genetic research would lead to new treatments which, with societal and lifestyle changes, would make it as manageable as blood pressure.