Residents of the former mining and steel towns of Easington and Corby are the most likely people in England to be obese, research suggests.
Credit reference company Experian and analysts Dr Foster Intelligence used data from two surveys to draw up an obesity map of England.
Obesity risk is 22% higher than average in Easington, near Newcastle, and 21% higher in Corby, Northamptonshire.
The lowest risk was found in the City of London and Kensington and Chelsea.
In fact, London boroughs recorded the 10 lowest levels of risk.
Halting the year on year rise in obesity among children under 11 by 2010 is a key government target, and is part of a wider strategy to tackle obesity in the population as a whole.
The Department of Health has warned that if no action is taken more than 12m adults and one million children will be obese by 2010.
The analysis looked at two major surveys, the Health Survey for England and the British Research Market Bureau's TGI quarterly survey of 25,000 Britons which ask people their Body Mass Index (BMI).
The postcodes of the respondents were then compared to a socio-economic classification system developed by Experian.
This enabled the researchers to show which types of people tend to have high and low BMIs.
As the make-up of each town according to these categories is known, they were able to rank towns on their density of the number of people likely to have a high or low BMI.
The researchers claim their form of detailed geographical analysis could help local health service planners and clinicians target resources where they were most needed.
Emily Sparks, a health consultant at Experian, said: "Through better health mapping, we can now provide timely and relevant information to enable the more effective targeting of communications and the delivery of preventative care to social groups and neighbourhoods most at risk of obesity."
However, Dr Ian Campbell, medical director of the charity Weight Concern, said obesity was a widespread problem - and doubted the merits of a highly targeted approach.
He said: "The management, prevention and treatment of obesity does not need fine tuning.
"The differences are small between regions, and we need a broad brush approach."