Obesity and overweight people are costing Birmingham health services more than £316 million a year, according to the NHS.
And that figure is expected to rise above £351 by 2015, unless residents - and particularly parents - can be convinced of the need for good diet and exercise.
The figures were revealed in a new report published by the NHS as part of a drive to encourage healthier lifestyles.
The report, called Healthy Weight, Healthy Lives, includes estimated annual costs to the NHS of diseases related to patients being overweight or obese.
For the three Birmingham health trusts, the current cost is £136.3 million a year.
Dudley, Sandwell and Walsall have a combined bill of £249.4 million, while Wolverhampton health trusts are spending £73.8 million. In Solihull, the NHS is spending £51.4 million dealing with the effects of obesity or overweight patients.
The new figures are the first time the cost of obesity has been calculated for each health trust.
A study published last year warned the national cost to the health service was £4.2 billion in 2007 – due to rise to £6.3 billion in 2015.
The new report is designed to offer advice to health authorities and local councils on how to deal with the problem.
But it warns that obesity is ultimately a result of poor diets and lack of exercise, and can only be solved by people changing their lifestyle.
In particular, parents must act to ensure their children are encouraged to eat healthily and take part in physical activity. But the report also contains the results of a study showing that most parents fail to realise when their child has a problem.
Jut 11.5 per cent of parents with overweight or obese children recognise that their children is overweight.
Parents also underestimate how much unhealthy food and convenience food they buy, and overestimate the amount of activity their children do.
Only 38 per cent of adults know that obesity can lead to heart disease and only 6 per cent know about the link of being overweight to cancer.
Sir Liam Donaldson, the chief medical officer, said: “The link between obesity and preventable illnesses, such as diabetes, heart disease and cancer is undeniable. In England almost two-thirds of adults and a third of children are either overweight or obese; without effective action this could rise to nine in ten adults and two-thirds of children by 2050.”
The NHS report called on councils and local health trusts to consider giving parents cooking lessons, and advice on buying the right products in shops.
It called on local bodies to consider interventions including “shopping and cooking – giving parents and their children the knowledge and skills they need to shop for and prepare healthy meals.
“This will include challenging the belief that ‘kids’ foods’ and ‘convenience foods’ offer better value than fresh, healthy foods.”
And the report warned that some parents are actively hostile to the idea of health.
It said: “Concepts such as ‘health’ and ‘healthy lifestyles’ can be alienating terms to families most at risk of problems.”