There is no problem with dietary research. The 'problem' is by design.
Both people doing the research and people funding the research know very well that what the flaw of this approach is, but just chose to do the shoddy job that they do because it brings in money. If it's not by design then there is a worse conclusion - the researchers/funders are incompetent. It's most likely a mix of incompetence/corruption.
Both people doing the research and people funding the research know very well that what the flaw of this approach is, but just chose to do the shoddy job that they do because it brings in money. If it's not by design then there is a worse conclusion - the researchers/funders are incompetent. It's most likely a mix of incompetence/corruption.