You can find papers on anything if you put in the keywords. They'll also study bogus new age things, just to try to settle the actual science (and in some cases the papers will be from subpar journals that still get indexed. Pubmed has a big warning label that a paper being there doesn't mean the contents are endorsed by NIH.

Here are results for homeopathy https://pubmed.ncbi.nlm.nih.gov/?term=%22homeopathy%22 and fad diets https://pubmed.ncbi.nlm.nih.gov/?term=atkins+diet

In this case, the list is low tier papers and journals, or some systemical survey type papers (or low quality first order papers) that still don't reach any conclusions.