Office workers who stand at their desk for three hours a day lose around 30,000 calories - or 8lbs - over the course of a year, an expert on physical activity and exercise has claimed.

According to Dr John Buckley of the University of Chester in the UK, standing at an appropriate height-adjusted desk for three hours per day will burn 144 calories in that time - amounting to over a half a stone in a year.

"This is the perfect way for any office-bound worker to achieve the typical New Year's resolution of wanting to lose half a stone without changing anything else - how easy is that?" he said.

Dr Buckley applied his knowledge of human physiology to make the calculation.

He noted that over the past 50 years, participation in sport and exercise has remained largely the same.

"So it is sedentary behaviours, such as sitting at a desk, and nutrition which are the key factors causing the typical annual increase in most people's waistlines," he explained.

He noted that past standing desk enthusiasts included writer, Ernest Hemingway, US president, Thomas Jefferson and UK prime Minister, Winston Churchill.

Meanwhile, Dr Buckley also encouraged office workers to use the stairs as much as possible, instead of lifts and escalators.

"It's little changes in behaviour such as this, or standing at your desk, that can add up to make quite a big difference to your health," he added.