I had reasonably well-educated parents. Both worked full time however and our diets did suffer because their childcare arrangements were not great.
Breakfast, if we had it - frosties with semi-skimmed milk. Lunch was a sandwich on white bread filled with some sort of paste. Packet of crisps, chocolate biscuit. One piece of fruit (apple.) Drinks - coke/Ribena. Weekends was always a pie and cake 
Evening meal - something my mother had cooked; these were usually OK. We'd snack on crisps/yoghurt/biscuit before tea. Might have a banana before bed.
Most children I know now have wholegrain cereal for breakfast. Sandwiches or pasta salad on wholemeal brea. Raw veg, yoghurt, oatcake. Water to drink. Snacks are fruit/more raw veg. kids should be very fit and healthy!