Office workers trapped behind their desks all day should push away their chairs and work standing up, recommends an exercise scientist.
Standing up for three hours extra a day would burn off 8lb (3.6kg) of fat each year, says John Buckley, from the University of Chester.
Leading by example, Dr Buckley is using a standing desk which is believed to date from the 1940s.
"There is no need to sit down so much," says Dr Buckley.
Anyone feeling Christmas-pudding shaped after the holidays should consider standing rather than sitting at work, says Dr Buckley.
There are custom-made computer desks for anyone wanting to stand as they answer their emails - or else old desks can be set at a height for standing.
This upright stance was championed by Ernest Hemingway, whose vigorous prose was matched by this more physical approach to writing.
"Writing and travel broaden your ass if not your mind and I like to write standing up," wrote Hemingway in a letter in 1950.
Vladimir Nabokov was another writer who preferred to stand.
Dr Buckley, from the department of clinical sciences and nutrition, says that switching from chairs to working standing up will reduce obesity and improve circulation.
Standing up for three hours will consume 144 calories, he says.
"People are sitting down at work, then sitting in the car and then sitting down in front of the television," says Dr Buckley.
"Your metabolic rate crashes to an absolute minimum.
"It isn't natural. Humans are designed to stand up and keep moving."
Dr Buckley is part of an advisory group, working with England's chief medical officer on responses to obesity.
There have been several recent reports warning about the sedentary nature of work and recreation.
A study in the autumn made a strong connection between too much sitting down and an increased risk of diabetes.
A previous study warned that a sedentary lifestyle could be causing as many deaths as smoking.
Dr Buckley says that regular changes in the workplace can make a long-term improvements.
"It's little changes in behaviour... such as standing at your desk that can add up to make quite a big difference to your health," he says.