Back in the 1970s-early '80s when I was in the Navy I was fortunate to have a job that included low level assistance to some researchers for the NIH, Walter Reed and national and regional Naval hospitals. We Corpsmen and Army medics mostly did grunt work per specs given by the researchers: inject this in test subjects, draw blood or other fluids for that in test subjects, prep lab specimens, etc.
It gave me an appreciation for how meticulous and ethical research should be, and usually is.
But I've learned to be skeptical about some biased agendas foisted off as "research" regarding diet, some pharmaceuticals and, more recently, viruses. I would have thought we'd have learned something from the first SARS pandemic in 2004, but some of the utter hogwash and politically loaded nonsense published on some formerly reputable sites, including PubMed, has triggered my journalist's instincts to check the credentials and backgrounds of any researchers before passing it along to friends or family.
And I'm skeptical of any dietary claims or recommendations that don't include genetic profiles. For better or worse, humans tended to "evolve" to adapt to the predominant available diets in their regions. If they couldn't adapt and thrive, they didn't pass along their genetic material. While interbreeding has lent more adaptability to many of us, it's still not a factor for much of the world. But genetic profiling to identify optimal diets would likely meet with obstacles nowadays, so most of us must get along by trial and error, finding diets that suit us best.