I won't say precisely which generation by name. But hear this... genuine fact of my generation. My generation was taught in middle school health education class that two slices of pizza are a balanced meal. Pepperoni or sausage: meat. Cheese: dairy. Tomato sauce and/or onions: vegetable. Crust: grain.
These days, such a description is considered to be a sarcastic musing from people who don't spend a lot of time worrying about what they eat. Back then, it was practically gospel because that's what the health teacher endorsed.
All this and more, while everyone just can't figure out why there always has to be such a huge gap between old school and new wave. We can't even manage to carry the same fucking lesson plan from one generation to the next, but we expect a coherent society? Good luck, folks!