Even all the so-called healthy cereals were still just sugary desserts masquerading as health foods. They might have replaced GMO corn flour with organic corn flour, for example, or added in a couple of measly grams of soy protein, but ultimately these were just incremental improvements on the even less healthy cereals that preceded them. And so most people who cared about their health simply stopped eating cereal. They grew up, but their cereal never grew up with them.