A controlled environment of people not changing their diet and lifestyle in a 20 year time span.
There's plenty of studies like that.
There are quality studies where p-values tell that their sample size isn't large enough, but when you do a meta-analysis of studies with same methodology you get a relevantly sized sample.
I do guess you are talking about those "Phd nutrition guys" and yes, they are full of bullshit and aren't scientists, because if you are talking about the real science, your comment is full of disinformation.
And what you suggested isn't at all uncommon in those quality work studies.
Checkout https://en.wikipedia.org/wiki/China%E2%80%93Cornell%E2%80%93...
A controlled environment of people not changing their diet and lifestyle in a 20 year time span.
There's plenty of studies like that.
There are quality studies where p-values tell that their sample size isn't large enough, but when you do a meta-analysis of studies with same methodology you get a relevantly sized sample.
I do guess you are talking about those "Phd nutrition guys" and yes, they are full of bullshit and aren't scientists, because if you are talking about the real science, your comment is full of disinformation.