Review Reports

Round 1

Reviewer 1 Report

Authors differentiate between the transient microbiota variations in response to acute dietary intake/changes vs. the long-term effect of dietary habits on gut microbiota composition and have the objective to evaluate the latter. However, the study design which characterizes a single fecal sample does not control for the acute effect of the foods consumed in the hours preceding sample collection.  

 

Similarly, the FFQ used - even though it is supposed to survey participants’ habitual dietary intake of the last 12 month - does not only reflect participant’s habitual intake but could also reflect rarely eaten food items (< 1 week). 

 

This could be controlled for by a food diary (if available at sampling collection) or by comparing results with and without foods consumed < 1 week. Otherwise, this should be discussed in the limits of the paper. 

 

Did the authors try to perform pairwise permanova (especially between BMI categories)? 

 

Minor comments

- Figure captions appear twice

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 2 Report

This is an important study related to diet and microbiota in a large Chinese population. However I have some concerns: the subjects are considered healthy based on negative colonoscopy; however they could suffer of IBS, microscopic colitis etc or other conditions like BMI abnormalities, all able to create a bias. Therefore authors should comment this at lage in the discussionc chapter. Authors should also specify how typucal is this group of subjects for the Chinese population.

Author Response

Please see the attachment.

Author Response File: Author Response.docx