Shoppers were encouraged to Change4Life by eating less fatty food and taking more exercise to help Watford become “fitter, healthier and more active”.

The NHS-sponsored Change4Life roadshow rolled into the Harlequin shopping centre on Wednesday where visitors to the stand, outside HMV, were entertained by a young footballer demonstrating his “Keepy Uppy” skills, Watford's Fujian White Crane Kung Fu martial arts group and Bollywood dancer Gopi Keilman.

They also saw a cookery demonstration from nutritionist and Masterchef quarter-finalist Danine Irwin, from Bushey, who encourages children to enjoy healthy food.

Stuart Bloom, chairman of NHS Hertfordshire, said: “This is all about showing people they can live healthy lifestyles. They need to take responsibility for themselves by eating healthily and getting exercise. It really does make a difference to how you feel and your well-being.”

Mr Bloom said Watford was “slightly above average” regarding the number of adults and children in Hertfordshire who were considered overweight or obese.

He said: “We need to do better than average. The better people live in terms of lifestyle, the less need they will have for the NHS. We would rather have prevention than the cure. There's a lot they can do to keep well.”

NHS Hertfordshire goes into schools to weigh children in Reception and Year 6.

The results of the National Child Measurement Programme for 2008/09 found in Watford that 22.5 per cent of four and five-year-olds, and 31.2 per cent of ten and 11-year-olds, were classed as overweight or obese.

The East of England average is 21.8 per cent and 30.7 per cent respectively.

Meanwhile, the latest Department of Health profile for the town showed nearly one in four adults (22.8 per cent) have a Body Mass Index (BMI) of more than 30, compared to 23.6 per cent in the region.

The healthy range is between 19.5 and 25, while people are considered overweight if their BMI (their weight divided by their height) is between 25 and 30 and obese if it is greater than 30.

In addition, people considered to live a healthy lifestyle could live up to nine years longer than those who do not, according to life expectancy figures for Hertfordshire.

Mr Bloom said: “We do weigh children and too many kids do start school already overweight and it's very difficult to encourage them to get down to what you would call a healthy weight. But it's not difficult to do.

“Sometimes we see overweight parents and they breed overweight children. We need to break that cycle.

“If you get into any habits of a healthy lifestyle at a younger age, you're much more likely to keep well and hopefully live that much longer. It really does add years to your life.”