Monday February 18 2008
Dieters who have managed to shed their excess weight need to do 90 minutes of exercise a day to keep the pounds off in the long term, according to a study.
The finding comes as a leading nutritional researcher called on world leaders to tackle obesity with the same urgency as global efforts to tackle climate change.
Rena Wing, professor of psychiatry and human behaviour at Brown University, told the American Association for the Advancement of Science meeting in Boston yesterday that exercising 60 to 90 minutes a day was essential to long term weight loss. By studying data on more than 5,000 men and women who have, on average, lost 70 pounds and kept the weight off for six years, she found that successful dieters had high levels of physical activity and consciously controlled their eating habits. This meant frequent weighing, following a consistent diet across the week and taking quick remedial action at the first sign of weight gain.
"There's no way around it," Wing said. "If you want to lose weight and keep it off you need to really change your lifestyle, particularly if you're overweight or have a family history of obesity. The obesity epidemic won't go away simply because people switch from whole to skimmed milk. They need to substantially cut their calories and boost their physical activity to get to a healthy weight – and keep minding the scale once they do."
In Britain more than one-fifth of adults are obese and, of the remainder, half of men and a third of women are overweight. Obesity is linked to heart disease, diabetes and premature death. By 2015, 2.3 billion adults are forecast to be overweight, including 700 million obese.
Philip James, of the International Obesity Taskforce, told the seminar urgent steps were needed to transform the environment that makes people fat. James, who chaired the UN Commission on the Nutritional Challenges of the 21st Century, said obesity was a problem for all of society, arguing that blaming individuals for their vulnerability to gain weight was no longer acceptable when the "environment in which we live is the overwhelming factor amplifying the epidemic".
He added: "It is even more naive to tell people that they just need to make a little change in their eating habits or their daily activity and suddenly the obesity problem will be remarkably easily solved."
A big challenge for the food sector would be to transform its products to reduce the promotion and abundant array of high energy foods, he said.