Feeling guilty about not doing enough exercise? Well, guilt might soon be the least of your problems.

Thanks to a new Big Brother-style gadget being adopted by American companies — and coming to Britain early next year — bosses can measure exactly how many calories you are burning in a day and compare the data with “performance benchmarks”.

In other words: staying in shape might soon become as important as getting to the office on time.

The gadget, from the Dutch electronics company Philips, is slightly larger than a postage stamp and must be carried around at all times, either in a trouser pocket or on a necklace.

It monitors exactly how much exercise you do throughout the day, and the intensity of it, before uploading the results to a central website, using a USB connection. It is waterproof, so even scrubbing yourself in the shower counts towards your daily tally.

So far, about 25,000 workers at 30 large companies in the US are using the device, which Philips is selling under the brand name of DirectLife. Erik de Heus, chief executive of Philips’s Wellness Solutions division, told The Times that he had lost more than half a stone after using the device. “You find it’s the little things that count, like taking the stairs instead of the elevator, or walking to the coffee shop instead of driving there,” he said. The service does not end simply with a calorie-burning statement at the end of each week. Philips also provides a personal fitness coach, who sets daily targets and long-term goals, and gives tips on how to fit exercise into a hectic schedule. The coaches, who communicate via e-mail, are also trained in “behavioural psychology”.

The scheme, which was shown off at a high-powered conference in Coronado Island, California, attended by President Obama’s healthcare adviser Ezekiel Emanuel and celebrities including Goldie Hawn, comes as American companies are desperate to lower their healthcare costs.

The US spends twice as much on healthcare as Britain, with much of the expense met by companies. A third of all healthcare costs for the over-40s is thought to be related to lack of exercise. The price of a family health insurance policy can top £8,000 a year and there is no public healthcare system to fall back on.

Privately, experts believe that by enrolling in schemes such as DirectLife, employees might eventually be able to get cheaper insurance. Officially, however, Philips says DirectLife is aimed at the 60 per cent of the population who do not reach the recommended minimum level of daily exercise.

As for concerns over privacy, Mr de Heus emphasises that the scheme is voluntary and that users’ statistics are private unless they choose to share them. However, CEOs will be able to see “aggregate data” for their entire workforce, and then compare it with similar data from rival companies.

There is, of course, one flaw to the otherwise highly sophisticated technology: it can’t measure what you eat. Not yet, anyway: a calorie-sensing skin patch isn’t far off, experts say.

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