In the sixties we would eat things like roast chicken dinner or steak pie and potatoes (Sundays!), Stew and potatoes, mince and potatoes, always fish on Fridays (Catholics!), bacon, potatoes and cabbage fried in the bacon fat, ham salads on Saturdays - with chips and we had corned beef, potatoes and beans. We would have sausages, beans and mash or perhaps scotch pie and chips. We did eat vegetables - or at least it was put on the plate for us to eat, not always successfully. Thankfully my mother and father thought offal of any kind was disgusting so that wasn't fed to us, unlike some of my unluckier friends!
Every dinner had potatoes in some form. We never ate pasta or rice of any kind. That would have been far too exotic for us 
We ate only white bread. We always had real butter, never margarine. We only got fizzy juice like coke on special occasions like Christmas or holidays. I remember as we got older my mother bought diluting orange juice now and then.
We rarely had puddings, sometimes on a Sunday. Occasionally we would have home made soup and a pudding rather than a main meal. Cheap and easy.
We had toast for breakfast. For lunch we went home from school and had whatever was concocted for us, depending on which day of the week it was. Our favourite was when on a Thursday my mother made a few chips and boiled eggs and put some of each on a slice of bread for us. She treated it like a special treat and we loved it. In actual fact it was because my father didn't get paid until Fridays and there was only eggs and potatoes left to eat.
My mother was not a paragon of virtue as far as our eating habits was concerned, it's just that they had very little money to buy any of the crap that we can afford today. In fact I grew up thinking that my mother didn't like meat, but I now realise that she took potatoes, gravy and veg without meat because there wasn't enough to go round.
I think in many ways it might have been easier to feed children healthier back in the sixties if you had enough money to do so, as often mothers didn't work and had more time to cook from scratch. Today it's difficult for parents to both work fulltime, pick children up from childcare, go home and then cook a meal. Sure you could say they could batch cook at weekends, but often they have to do many other household chores as well as spend some time with their children.
I think, to be honest, that people in general are trying their best in difficult circumstances.