The obesity pandemic has taken the world by surprise and there is an urgent need for bold solutions, says an international expert.
Professor Shiriki Kumanyika, chair of a panel that wrote an obesity report for the World Innovation Summit for Health in Doha, said it was a relatively new problem and an unintended consequence of technological progress.
"We have been asleep at the wheel," she said at a discussion about the report, which describes obesity as a grave threat to national health systems and economies.
"We have to get a handle on food supply. Our report recommends that countries find innovative and economically feasible ways to reshape their food system."
These could include taxes on unhealthy foods and infrastructure changes to ensure affordable fresh food reaches remote areas.
"There is more of a contribution from overeating than there is from being inactive," she said.
"It is too easy to eat 500 or 1000 calories too many. You can do that in one meal. You can't work off that number of extra calories in a normal routine."
Solutions could also involve improved programs at schools and workplaces, as well as weight screening for children and special weight management training for health workers.
"There need to be big-picture changes on a global scale, but on a local level schools, employers and primary health care have to be part of the solution," said Prof Kumanyika of the University of Pennsylvania and a member of the International Obesity Task Force.
"Obesity is hard to talk about. It is a personal problem. But it is also a complex and urgent world health problem."
Former UK education Minister Baroness Tessa Blackstone said prevention had to involve entire governments, not just the minister of health.
She said telling people what to eat could be described as introducing a nanny state.
"But that's rubbish. We have to push aside that sort of criticism."
Blackstone noted that obesity often ran in families, and said schools should reach out to parents to ensure children ate sensibly and exercised.
"There are many parents who do not know enough about the damage that is being done to their children by some of the food and drink that they are giving them."
* Clifford Fram is in Doha as a guest of the Qatar Foundation.