Children's health is being damaged and their lives shortened because they are eating too much salt and salty food. See Children are vulnerable to salt. It is important to protect children from processed foods/salty snacks/ready meals and the like. Children are more at risk from their salt intake than adults are.
Children are especially vulnerable to salt because of their small size and small blood volume, and because their blood vessels are weaker than those of adults. Salt, and the water it attracts to it, can more easily distend weak blood vessels than fully mature ones. The resulting increase in blood volume and other fluid retention results in weight gain, as well as higher blood pressure and many other undesirable consequences. The smaller the child, the less salt they should have - and a baby, of course, should have no salt at all. - Babies can die if they are fed salty food.
Because children have much smaller bodies than adults it would be best if they had no more than half as much salt as adults. Most children, however, have much more than this because they eat so many snacks and instant foods. Just one cheeseburger, for instance, contains almost double the recommended daily salt maximum for children. There are high amounts of salt in packet soups, instant noodles, ketchup and sauces, sausages, burgers and savoury snacks. Fat children will lose weight fast if they eat less salt. And even faster still if they eat plenty of fresh fruit and unsalted vegetables, because these are rich in potassium, which helps to displace sodium from the body. Overweight children should not be put on a diet; dieting is harmful and unnecessary and does not usually result in weight loss. Once children start dieting it is often the beginning of a lifetime of yo-yo dieting and increasing weight and ill-health.
Unfortunately bread contains a lot of salt and most families eat quite a lot of bread because of using it for sandwiches in packed lunches, and for toast, etc. Because of its high salt content bread is not a healthy food for little children or for anyone who is overweight. Some bread manufacturers have lowered the salt content of certain loaves, but most bread still usually contains 0.5g or more of sodium per 100g. This is too much. - Always check on the packet; look for the lowest sodium content.
Cheese is often recommended as being good for children because it contains calcium, but cheese is not really good for children because it has a high salt content. So don't give them a lot of it. Children can get plenty of calcium by drinking milk and by eating dairy yogurt (but avoid non-dairy yogurt and low-fat yogurt and the sort of yogurt that has added sugar or sweeteners, colours or other synthetic chemical additives).