The first half of her book talks about nutrition and health but the second half talks about her company that offers services to give people personal guidance on nutrition and monitoring their health, so there are some attempts to do this. https://www.caseymeans.com/goodenergy

Or in researching nutrition

I don’t know why this is downvoted. The lack of profit motive is a big reason that nutrition and supplements aren’t as well studied through rigorous trials as drug therapies. The ones that are run are funded by grants. Rather than just “more funding” I think there needs to be more systemic ways at reducing the cost of clinical trials or using alternate methods of getting high quality scientific data for answering these questions.

For example, there is a good trial running now on ketogenic diet in glioblastoma patients, NCT05708352, I think with a NIH grant and maybe the NCI as well. Here is a video about it: https://www.youtube.com/watch?v=W31kR0MzyRA

Food and nutrition is a big business though.