A third of British adults are always on a diet, a new survey has revealed.

The poll of 2,000 Brits by supermarket Tesco found that 15 per cent of over-55s restrict what they eat every day – double the percentage of any other age group.

The news follows an announcement by a leading UK insurer that it would offer cheaper health insurance premiums for those who use the gym regularly.

“It's important that we do take our weight seriously, and monitor our food intake and activity levels regularly,” said Weight Concern's Medical Director Dr Ian Campbell.

“Two thirds of us are already overweight. However, we need to move away from the concept of dieting towards one of healthy diet.”

The survey found that 15 per cent of adults spent at least half an hour a day worrying about their weight, while one in 20 women worried for more than three hours.