I find more insight and less conspiracy in "History of breakfast" from Wikipedia[1]. The Wikipedia article talks about different perspectives before 1800 since it is not clear why the article is talking about the American breakfast instead of focusing on different cultural perspectives (e.g. "Before cereal, in the mid 1800s, the American breakfast was not all that different from other meals").

[1] https://en.wikipedia.org/wiki/History_of_breakfast