From the article’s “key takeaways”:

> By considering interindividual and intraindividual differences in transit time in human studies, diet–microbiota interactions and disease-related microbiome signatures may be better elucidated.

There is also an entire section entitled “The role of gut transit time in health and disease”

None of this is summarized in the posted article. It's in the research paper which I didn't read because the article seemed like fluff.