Staff planning their office Christmas party may have to think again before ordering all the trimmings and mince pies. The boss could be expecting them to step on the scales the morning after.

Weight Watchers plans to get nine-to-fivers fit by selling its dietary services to companies the length and breadth of the nation. It is offering to run classes during the lunch hour or immediately after work, when its staff will give out advice on what food and drink to do without in order to bring the belt down a notch.

The scales will be brought into the office once a week for “weigh-ins”. Confidentiality is promised, although one suspects mischievous colleagues will find ways of obtaining those terrifying numbers.

The scheme was devised by Mads Ryder, a Dane who took over last month as senior vicepresident of Weight Watchers UK. He believes that up to 500 companies will join the programme, which begins in the next couple of months. Waitrose, the supermarket chain run by Mark Price, the self-styled “chubby grocer”, is among those understood to have expressed an interest.

Mr Ryder, who lost 26lb (12kg) on one of his company’s weight-loss courses last year, said: “There’s a lot of companies that want to take more care of their employees and offer more than an overall package.

“For the employer it will help cut healthcare costs and cut down on the number of days staff are off sick, and I don’t think employees will have a problem with taking part.

“In the US we do this and it’s more than 10 per cent of our business there. Losing weight makes you more confident about yourself and improves your ability to do your job.”

The move comes amid growing concern about Britain’s obesity crisis. The Local Government Association forecast last month that one million children would be obese by 2012 and that social services may increasingly have to intervene.

A number of councils in the North of England were reported to be under pressure to divert money from services, such as helping dementia sufferers, to tackle the weight problem.

Staff absence from the workplace is thought to cost businesses more than £13 billion a year, with an average of 6.7 days lost per employee in 2007.

Weight Watchers traces its roots back to 1961 when Jean Nidetch, an American from Queens, New York, called a group of friends round to her house and admitted that she was obsessed with eating cookies. She found that meeting in a group was the best way to lose weight.

She teamed up with a businessman and founded the Weight Watchers company, based on forming similar support groups for people wanting to shed the pounds.

The company was introduced to Britain nearly 35 years ago and now has one million members, who monitor their calorie intake by giving each food a number of points and setting a maximum number they are allowed each week, or following one of the company’s diet sheets.

A range of Weight Watchers food and drink products generates £170 million of sales a year, making it the 14th-biggest brand in the country – higher than Pepsi.

Mr Ryder said: “At the end of the day there are all these shakes and soup diets, and other fads, but the problem is with these that once you stop them you just go back to your bad habits. We are about changing attitudes to food.

He added: “I think that rather than obesity we now have globesity – every government claims it’s got the biggest population. I have to say that unfortunately the UK is one of the leading countries in terms of a growing obesity problem. I think the UK is catching the US up fast. I’m going to make the Brits fitter!”

Sarah Ferguson, the Duchess of York, remains a devoted supporter of Weight Watchers after crediting the company for changing her life. She became a spokeswoman for the company in the US in 1997 and has been granted life membership.

Heavyweight business

— Weight Watchers was founded in 1963 when Jean Nidetch, an American housewife from Queens, New York, persuaded some friends to join her in following a medical diet recommended to her by her hospital dietician

— Four years later the first meeting in Britain was held near Windsor

— 50,000 Weight Watchers meetings are held in about 30 countries each week, including 6,000 in Britain

— It became a public company in 1968 and ten years later was bought by the HJ Heinz Company. In September 1999 Artal Luxembourg SA took over ownership

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