I'm having deja vu. We had a top story on HN recently where either the article or the consensus of the comments was "you pretty much cannot believe any studies about food or nutrition."
The problem is that humans are incredibly complex and diverse, react to stuff in wildly different ways, and you cannot A/B test on the same individual, as you cannot reseg it to the same starting state, you cannot run two experiments on them, and you cannot get two completely matching people.
And it's somewhat-to-entirely unethical and logistically impossible to conduct even uncontrolled studies over a human's entire lifespan, which is really what we're talking about here. I don't think anybody is worried that eating eggs every day will cause health problems for an otherwise-healthy 25-year-old.