If you compare the meals served in many of the kitchens today to meals served 100+ years ago, there is one very big difference. Nearly every meal served in North America has at least one dish that has come from a box, bag, or pouch.
Take breakfast, for example. Did you have toast? If so, did you make the bread? Cereal? One of those little packs of Quaker oatmeal, all flavored up and just waiting for you to add water? Did your breakfast originate in the freezer? Frozen toaster versions of pancakes, waffles, and pastries abound in many kitchens.
Several years ago, I did a "Scratch Challenge" during which everything we ate had to be made from scratch – no convenience ingredients allowed. It wasn't until I did this that I realized that even in my fairly "clean" kitchen, there still remained a lot of processed items.
If you do a quick survey of your own kitchen, you may be surprised at what you find. I discovered that the best way to clean up my act was to focus on cooking only from scratch. Now, my kitchen has only a few holdouts, most of which are there for food storage purposes.
Some of the most common processed items that "sneak in" are dairy and grain products: