Nothing wrong with chips unless it is in excess, Bags, (have just been watching, "The men who made us fat" with horror). The problem is the child who day after day, as others have already said, has a lunch box with a chocolate bar, crisps, something fizzy and brightly coloured on a stick and nothing else. Some might say this is none of the school's business, but a hungry child cannot learn and a child full of sugar can be hyperactive and disruptive. This is the school's business.
I also think it is interesting that we rarely point the finger of blame at the food industry.