I do recommend the studies of the global burden of disease project as an authority for what is healthy [1] Springman, cited on chapter 5 of the report, goes into depth relying on those evidences for modeling the potential diets. [2]

That is what the IPCC references. Great work, published in nature, peer reviewed and pretty solid science.

[1]: http://www.healthdata.org/gbd [2]: https://eatforum.org/eat-lancet-commission/