> Some limitations to this study beyond the subjective nature of the term “mood,” are compliance with following the study protocol, lack of exact control over the first and final diets, and uBiome’s bankruptcy that limited sample size further than expected.

This is what you're looking for: it's a pilot study seeded by now-disgraced/bankrupt uBiome.

This should be the top comment.

Don't go too heavy on the salt.

I suppose without further research we won't have any clue what effect salt will or won't have on my emotional state ;)

But seriously, there is pretty much no point discussing the conclusions of such a deeply flawed paper.

Most grants fund large projects out of which smaller papers are written. I don't think any grant is funding individual papers like you seem to imply

Absolutely right. This is not even a proper pilot study.

This was going to be my comment too. N = 20 is atrocious and that too only over 2 weeks. Think any significant, measurable changes to mental health outcomes would probably take a lot longer than that to manifest. I further find results from any kind of "food recall" surveys (or just surveys in general) hard to believe. Stated vs. revealed preferences/outcomes should be a bigger debate imo.

Any major changes to gut biome will definitely take more than two weeks. Anyone who has ever had to do an elimination diet will tell you that it can take 4 to 6 weeks for things to normalize when making dietary changes.