> high IQ

Therein lies the rub, the controversy mostly comes from people who reject the very premise of IQ.

IQ is highly correlated with nutrition. Very likely, being food-insecure has a direct causal effect of lowering IQ. It isn't a thing fixed from birth.

So is height, and historically there have been large differences in height between the rich and poor. In modern developed countries, however, there doesn't seem to be any significant difference based on socioeconomic level. That leads me to believe that these "nutritional deficiencies" don't exist and are not what is causing any observed gap in IQ or academic achievement.

Do Asian Americans have better nutrition than other categories?

It would seem so. CDC statistics show that people who identify as Asian have a lower obesity rate compared to other racial and ethnic categories. Obesity is known to cause decreased cognitive function.

https://www.cdc.gov/obesity/data/adult.html

Correlated, yes. Highly correlated - I doubt it. Einstein didn't get that way by eating enough blueberries and salmon oil or whatever.

Now of course, if you are raised on a diet of sugar and lead-laced air and water, you won't reach your natural genetic potential. And if you are raised by billionaires with a live-in chef and nutritionist and tutors, in a place with squeaky-clean air and water, you might reach your full potential.

But those things merely optimize, or impede, the raw material you were born with.

You can hide a high IQ with starvation, sleep deprivation, withholding books from a child, and stress hormones from an unsafe environment.

Interesting.

There was quite a significant difference between my IQ results and my standardized testing scores (based on percentile rankings -- IQ => higher rankings).

(FWIW, I think both test are utter horseshit anyway.)