Eating well throughout adult life improves physical fitness in old age, a study has found.

Researchers looked at the diets of 969 British men and women whose lifestyles had been monitored since they were born in March 1946.

At four points in their adult lives, starting at the age of 36, their eating habits were compared with standard measures of mobility and fitness when they were in their 60s.

People who ate more fruit, vegetables and wholegrain cereals and fewer highly-processed foods performed better in all the tests.

Lead scientist Sian Robinson, a professor from the University of Southampton, said: “Improving the quality of your diet can have a beneficial effect on health whatever your age.

“However, this study suggests that making good dietary choices throughout adulthood – by cutting down on highly-processed foods and incorporating more fruit, vegetables and whole grains into your diet – can have a significant beneficial effect on strength and physical performance later in life, helping to ensure a much healthier old age.”

People who ate more fruit, vegetables and wholegrain cereals and fewer highly-processed foods performed better in all the tests

Three fitness tests were employed that involved rising from a chair, “up-and-go” standing and walking, and balance.

Compared with those who had eaten a poorer diet all their adult lives, healthy-eating participants performed better in each test.

There was also evidence of enhanced performance in two measures, chair rise speed and standing balance time, among participants whose diets had improved across adulthood.

The findings appear in The Journals of Gerontology: Series A.

Professor Cyrus Cooper, director of the Medical Research Council Lifecourse Epidemiology Unit (LEU) at the University of Southampton, said: “The link between dietary patterns and frailty in older people will open the door to effective interventions against the age-related decline in musculoskeletal function which is such a growing cause of disability in ageing populations worldwide.”

For the chair rise test, researchers timed how long it took for a participant to stand up and sit down again 10 times in a row. The up-and-go test involved rising from a chair, walking three metres at a normal pace, returning to the chair and sitting down.

To test balance, the scientists recorded how long a participant could stand on one leg with eyes closed.