The difference between the Midwest and LA is also how fresh the produce is. Most of the produce in the US comes from California so it would make sense that the biggest metro areas closest to the fresh veg and fruit would focus on eating healthy and nutritious foods. The Midwest is the home to some incredible cheese and ice creams, likely much more dairy as a whole. The amount of cow in Midwestern meals is what one would expect the same way proximity to the produce influences CA cuisine.