As the global obesity epidemic spreads, and the UK's Food Standards Agency prepares to debate the increasing number of overweight children, all eyes are fixed firmly on expanding waistlines.
A case of mind over matter?
But should we be looking elsewhere in the body for the real secrets behind this considerable health threat?
Scientists at the Universities of Edinburgh and Newcastle-upon-Tyne are about to embark on one of the biggest studies of its kind into the role the brain plays in making people fat.
It is a multi-million pound five-year project, the results of which could be crucial to the battle against weight-related illnesses like diabetes and heart diseases.
The theory behind it is that many people fail to lose weight, not because they cannot stop eating, but because the brain will not let them do so.
Previous studies have shown that once a person gains extra weight, the brain 're-programmes' itself to accept this as normal.
Any subsequent attempts to reduce the weight are then interpreted as a threat to the body's survival.
As a result, the brain automatically slows the body's metabolic rate to reduce the burning of calories.
Scientists involved in the study hope to find out exactly how the brain does this but think they already know why - evolution.
"Back in man's hunter-gatherer days, or even in Britain in the Middle Ages, starvation was common," says Professor Jonathan Seckl, an expert in molecular medicine at Edinburgh University.
"So the body learned to turn off its metabolism and go into survival mode so it could live through the famine.
"Now when somebody is obese and they try to lose weight, they immediately feel hungry and the body reacts as if they were a five stone weakling.
"It tells the brain 'I am being starved' and starts to retain calories like crazy."
Evolution lagging behind
Professor Seckl believes although famine has been almost unheard in the developed world for many years, evolution has yet to catch up.
This means that while food is plentiful, our brains have not yet re-programmed themselves to recognise that it's not always necessary to kick-start survival mode when food intake drops.
More and more people are obese
That process could take hundreds, if not thousands, more years.
"We are facing the pressure of millions of years of mammalian evolution," he adds.
"Yet the phenomenon of a McDonalds on every street corner is only something seen in the last 20 years."
The EU has set aside 11.7 million Euros for the project, which will involve 26 leading researchers from 13 different European countries.
The study comes at a time when an estimated one billion people round the world are overweight.
The UK's Food Standards Agency will launch a public debate on the issue later this week.
It will consider calls for food manufacturers to be banned from targeting children in adverts.
Culture Secretary Tessa Jowell has already asked the new television regulator Ofcom to look into the issue.
Ms Jowell, a former minister for public health, has said she is concerned about the rising rates of obesity in children.
The EU researchers hope to identify five or six new targets within the brain that could be used to develop new anti-obesity drugs.
One way might be to come up with a way of making fat cells burn up more calories by overriding the brain's control systems.
Professor Seckl said: "Before we can develop good medicines to stop the obesity epidemic, we need to understand how the body's own hormones regulate appetite and body weight."
But the project also touches on the sensitive question of whether millions of pounds should be spent developing drugs to treat obesity, rather than preventing it in the first place.
Scientists are acutely aware of the debate over whether obesity is an 'illness', or a self-induced state.
"There is a question-mark over whether we should be interfering with things like appetite," said Professor Seckl.
"A lot of people, and I am one of them, worry about that.
"But I see people all the time who are overweight and are driving themselves to distraction because they cannot diet effectively.
"Very few people, probably no more than 10% - 15%, are able to diet successfully and keep the weight off.
"Simply telling people not to eat does not really work."