The researchers studied data from three long-term studies, and found that under normal circumstances, older people gain one or two kilos every four years, but those who regularly eat foods containing nutrients, flavonoids, managed to stay in good shape.

The greatest effect was observed from the reception of flavonoids found in blueberries, strawberries, cherries and grapes.

Also these nutrients can be found in small amounts in tea, onions and apples.

Edin Cassidy, the lead author of the study from the University of East Anglia, believes that flavonoids slow down the rate at which the body absorbs fat, increase energy expenditure and helps maintain healthy intestinal bacteria.