A slim couch potato has poorer health prospects than an overweight person who exercises regularly, according to an expert who is urging people to end their weight-loss fixation.
Professor Adrian Bauman, director of the Australian Centre for Health Promotion, will address an obesity forum with the message that image-driven exercise is not helping the health of the nation.
"It's all about exercising to lose weight but the fact is many overweight and obese people don't lose weight when they start a regime and so most of them stop," Prof Bauman said.
"What they don't seem to be understanding is that it is far, far better for them to continue, even if they don't lose weight because they'll be much healthier for it.
"It's about health, not weight, but people don't seem to get it."
The forum of Australia's top obesity researchers has been convened to bust commonly-held myths surrounding weight, exercise, diet and general health.
Prof Bauman, of the University of Sydney, said there was growing evidence from large-scale epidemiological studies that being inactive was more dangerous for health than being overweight.
"They show that being healthy weight and active is best for health and being obese and inactive is the worst, but in the middle there was an interesting pattern," he said.
"It seems it's better to be overweight and active than it is to be slim and be a total couch potato."
He said the overweight active person was more likely than the slothful slim type to have a lower risk of cardiovascular disease and diabetes, and lower cholesterol and blood pressure.
Obese active people did not have the same advantage because the extra body mass had an adverse effect on metabolic processes, Prof Bauman said.
"The message is stop focussing on the weight loss only and think about your health in general."
The forum will be told there is increasing evidence that obese people who lose weight through dieting or exercise but gain it again, a process known as "weight cycling", are better off than those who remain statically obese.
"The early studies that suggested weight cycling could cause drastic things like premature death and heart disease were probably wrong," said Professor Lesley Campbell, of the Garvan Institute in Sydney.
Professor Bruce Neal, a senior director at the George Institute for International Health, will argue there is proof that weight kills, with overweight shaving one year off life expectancy and obesity taking three.
"And people who are morbidly obese lose about eight years," Prof Neal said.
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