Fast food is full of fat and salt; by eating more fast food people will get more salt and fat than they need in their diet.

Good food should be rich in vitamins and minerals, and also be low in saturated fat, salt and fast-releasing sugars and high in fiber.

Only 2 per cent of 268 salads checked at shops, cafés and fast-food chains had less than the 0.5g salt contained in a bag of Walkers crisps.