By Melissa Jackson
BBC News Online staff
Growing rates of obesity present a major public health problem for governments across the globe.
Two-thirds of UK men are overweight
In the UK, ministers have embarked on a public consultation exercise to assess just how best the tackle the problem.
However, medical experts fear initiatives will have little effect unless people start taking responsibility for their own health.
They are convinced there is no fix solution - the answer lies in the hands of individuals.
As the number of child and adult obesity cases continues to rise, people need to take stock of their lifestyle, they argue.
Governments can take a proactive role, and encourage people to adopt a healthy lifestyle - but if their efforts fall on deaf ears then they will have no effect.
The figures in the UK make for depressing reading. Over half of women, and about two-thirds of men in the UK are either overweight or obese.
How to start changing your habits
Always eat breakfast, preferably toast or cereal
Only eat when hungry
'Go large' on vegetables and fruit
Choose tomato-based sauces over creamy ones
Grill, bake or boil food instead of frying
Snack on low-fat foods like fresh or dried fruit and breadsticks
Park your car at the furthest end of the car park
Get off a bus a stop earlier
Increase your level of activity by a few minutes a day
Being overweight or obese increases the risk of heart disease, Type 2 diabetes, high blood pressure and osteoarthritis.
The estimated cost to the country is 18 million sick days, 30,000 deaths and £2bn a year.
The increasing incidence of obesity and its cost to the health service and society has prompted the government to target it as a matter of priority.
A new white paper on public health to be published later this year will outline ways of addressing the problem.
However, health experts say there is no mystery about how best to tackle obesity: if people want to stay trim, they must eat sensibly and make sure they take regular exercise.
Ian Macdonald, professor of metabolic physiology at the University of Nottingham Medical School thinks a few small lifestyle changes could make all the difference.
He said: "People should be exercising every day. This could mean walking up stairs instead of taking the lift or not driving to work or parking as far away from the workplace as possible.
"Small beginnings will make a big difference."
Professor Macdonald says the NHS has a role to play, but it lacks the resources to finance major programmes.
He said: "The NHS hasn't got the funding to go in for large scale health promotion. It can advise people but doesn't have the staff.
"It's not the health service's fault."
He believes obesity drugs may be useful, but there is a huge cost implication.
He said: "There is a long term benefit, but short term it will increase costs and there isn't the money in the system to pay for it.
"You will need a commitment from the tax payer because health costs will go up before they go down."
Dr Ian Campbell, chairman of the National Obesity Forum, is also sure that drugs are not the answer for all but the most severe cases of obesity.
"Weight management remains a lifestyle issue. Medication must only ever be seen as an adjunct to support people who have made efforts to change their lifestyle first.
"And once you have made a decision to manage your weight, it is something that you need to do for the rest of your life."
Dr Andrew Hill, senior lecturer in behavioural sciences at the University of Leeds, agrees that people need to take more control over their lives.
He said: "People need to put a bit of activity back in their lives.
"I would also like to see people spending a bit more time preparing food from their natural ingredients instead of buying packaged meals."
"We need to show some common sense and get food and eating back into our daily routine and give food some respect.
Obesity is a major killer
"There is no quick fix solution.
"I don't think information is the problem - it's the capacity to put that into action that we struggle with."
The idea of a fat tax - where duty on some high fat foods would be higher - has been suggested by the government.
Dr Hill believes it would be difficult to implement, but he thinks the government does need to do everything it can to spread a positive message about health lifestyles.
One way would be to inject more money into community initiatives at grass roots level.
He is a fan of the "free fruit at school" policy being set up by the government.
Under the scheme, parents on low incomes will receive vouchers to spend on fruit and vegetables as well as milk and powdered milk for babies.
Children in nursery school, who receive free milk, would also receive free fruit under the scheme.
It may be the best way to shape healthy eating habits in children and steer them away from weight and health problems in later life.