Breakfast cereal is a corn flake product made from refined grains, often infused with seed oils and artificial flavorings. You're not eating real food, you're consuming a mass-produced, highly processed imitation. Your body doesn't need this stuff, just eat whole grains instead.
Why trash
Grains stripped of nutrients, extruded at high heat, then 'fortified' with synthetic vitamins.
Try instead
Oatmeal with nuts and seeds, or Greek yogurt with berries.