Not all cereals are super processed, some cereals only have 2 or 3 ingredients.Saying "Americans are too stupid..." is too harsh and simplified for a complex subject but probably holds a kernel of truth.
For one, our economy has been good enough to create pretty good paying jobs that don't require the intensity of study that STEM subject do. Our kids role model influencers or sports stars, not scientists. And, when the influencer thing doesn't work out, most do OK in retail, real estate, customer service etc. Nothing wrong with those jobs, but they do not require the years of hard study.
Add to that, our health and nutrition affect us mentally- whether from mental health issues like depression or anxiety which make it harder to be driven or directly affecting cognitive ability. When 60% of the foods we eat harm us cognitively, we are not going to be at our best at the hardest subjects.
The Link Between Highly Processed Foods and Brain Health
Eating packaged foods like cereal and frozen meals has been associated with anxiety, depression and cognitive decline. Scientists are still piecing together why.
https://www.nytimes.com/2023/05/04/...e_code=1.mE4.iQAp.sDJtB4wW2FHN&smid=url-share
Now if you are talking about fruit loops, then yeah.