London - Expecting obese people to lose weight solely by "eating less and moving more" misunderstands the nature of the condition and will never solve the obesity epidemic, leading doctors have said.
In a staunch rebuttal to commentators who argue that obese people are to blame for not slimming down, experts from leading American universities say that the weight of chronically obese people is "biologically stamped in" - making it very difficult for them to lose pounds permanently.
Writing in The Lancet, they say recommendations just to cut back on high calorie foods might be "no more effective for the typical patient seeking weight reduction than would be a recommendation to avoid sharp objects for someone bleeding profusely".
Many obese people can lose weight for a few months, but between 80 and 95 per cent regain their lost weight.
This is because cutting back on calorie intake triggers biological systems that evolved when humans needed to survive in times of scarcity. In the modern environment, in which food is not just plentiful, but often highly calorific and aggressively advertised, these same systems make it hard for previously obese people to stay lean, the doctors write.
Dr Christopher Ochner, assistant professor of paediatrics and psychiatry at the Icahn School of Medicine in New York and lead author of the paper, said that in those with chronic obesity "bodyweight seems to become biologically stamped in and defended".
"Few individuals ever truly recover from obesity; rather they suffer from 'obesity in remission'," he said. "They are biologically very different from individuals of the same age, sex, and bodyweight who never had obesity."
Treatment of obese people should focus on weight loss surgery, and other measures that can reverse obesity-induced changes to the body's biology, they argue.
Leading British experts backed the Lancet paper. Dr Rachel Batterham, head of University College London Hospital's Centre for Weight Loss, said: "Once people have become overweight, then biology changes. An understanding of how difficult it is to lose that weight and keep it off needs to be communicated," she said.
Professor John Wilding, of the University of Liverpool's Institute of Ageing and Chronic Disease, said: "It is in reality much, much harder for someone who has dropped from 15 stone down to 11 stone, to stay at 11 stone, than it is for someone who has always been at 11 stone."
* The Daily Mail reports that critics said that medicalising the problem was "pandering" to obese people. Tam Fry, of the National Obesity Forum, said the old mantra "eat less move more" still worked if people were determined to keep weight off.
"Biology hasn’t changed much in the last 40 years, when no one was obese. People who want to lose weight manage to do so but it takes determination and some give in to gluttony," he said.
"If you want to stay slim and have determination you can," he added.
However Dr Ochner added that clinicians could not afford to ignore biological causes and rely on people changing their behaviour. He said: "Obesity should be recognised as a chronic and often treatment-resistant disease with both biological and behavioural causes."
He added that doctors need to be realistic.
Patients could improve their health by losing just 10 percent of their weight, he said - even though it may be disappointing for those with "aesthetically-driven goals".
The Independent, Daily Mail