Historically, there was a big food safety / “scientific nutrition” movement which was heavily influenced by the various food-safety issues around the turn of the previous century and also things like Great Depression / WWII-era concerns about malnourishment (my grandfather remembered all of the concerns that American teenagers hadn't been fed enough to be able to go toe to toe with the Germans).
This lead to a lot of truly regrettable food — when my grandmother did home economics classes the focus was always on things like having enough calories for manual laborers on a budget, cooking thoroughly to avoid the chance of disease, etc. which really emphasized meat and carbs, and techniques like pressure cooking (which allowed you to eat cheaper cuts of meat). Enjoying your food was not a priority. Her children were quite happy when she got into California cuisine back when that was new.
