PONE-D-20-26641

A 1-week diet break improves muscle endurance during an intermittent dieting regime in adult athletes

PLOS ONE

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Additional Editor Comments:

In general, the manuscript is coherent and well written with very few typos. However, there are concerns about the extent to which we can rely on these findings given the small sample size. The authors need to show that the study is powered to detect the changes (or lack of) described. If it is not, then it needs to be described as a pilot study, and the results discussed accordingly.

Abstract: line 26 to 28 , should age not be used to describe the participants rather than “before the 1-week diet break” ? Similarly, is height required to be reported here? Lines 41 to 44 , the summary is confusing.

Introduction: Please could you describe your pilot study more clearly from line 62. The aim of the study doesn't appear to fully fill the gap, which to my reading had been set out as understanding physiological, performance, cognitive and psychological changes during the diet break, rather than at the end of it.

Method: Could you give the gender split of the participants in this study from the outset? Results should not be provided in the method ( table one). Furthermore, in table one titles, you can just say 95% confidence interval , you don't need “lower limit to upper limit”. Line 177 to 178, I don't think you need to refer to the protocol here, or at least the way you do it seems strange.

Results: Line 230, age should be provided as part of the description of the participants rather than as part of the baseline measures . Again, it is not clear that height is important – furthermore, its measurements is not described in the method. Line 238 to 240 seems to be in the wrong place? Given the low number of participants in the study , it is quite useful to have the graphs of individual participant outcomes, but it might be helpful to consider which of these should be in the main part of the manuscript and which should go into an appendix (there is a lot of information here)? Also, it would be good to refer to why individual outcomes are useful in the main body of the text, otherwise, perhaps Table 1 is enough? In addition, given only 13 participants provided blood samples, is it worth reporting these data here (particularly given the apparent high variability in some of the measures)?

Discussion: It appears a bit contradictory to read in line 324 that the results may lack practical significance for athletes and then go on to discuss the practical significance of the results. I am not sure that you need to keep referring back to the introduction in the discussion. Given the small sample size(s) in this study, it is important not to overplay the results. For example, to what extent is the study powered to detect the various changes? Should the next step be to repeat the study using a larger sample and a controlled design?

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Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Yes

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2. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

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3. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: Yes

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4. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

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5. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: An observational study was conducted to determine the effects of a diet break on fat and fat-free mass, resting energy expenditure, muscle endurance, hunger sensations, and irritability. A total of 26 athletes were studied. No differences in fat mass were observed pre to post diet; however, a small increase in body weight was noted. Muscle endurance of the legs improved after the diet break; however, muscle strength did not differ. Significant differences were observed with respect to hunger sensations, prospective consumption, irritability and sensations of fullness.

Minor revisions:

1- Line 218: Indicate the specific type of Wilcoxon test. The paired test, analogous to the paired t-test, is the Wilcoxon signed-rank test.

2- Cite the statistical software used for the analysis.

5- State and justify the study’s target sample size with a pre-study statistical power calculation.

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Reviewer #1: No

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A 1-week diet break improves muscle endurance during an intermittent dieting regime in adult athletes – A pre-specified secondary analysis of the ICECAP trial

PONE-D-20-26641R1

Dear Dr. Peos,

We’re pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements.

Within one week, you’ll receive an e-mail detailing the required amendments. When these have been addressed, you’ll receive a formal acceptance letter and your manuscript will be scheduled for publication.

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Kind regards,

Chris Harnish, PhD

Academic Editor

PLOS ONE

Additional Editor Comments (optional):

Great work!

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation.

Reviewer #1: All comments have been addressed

Reviewer #2: All comments have been addressed

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2. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: (No Response)

Reviewer #2: Yes

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3. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: (No Response)

Reviewer #2: Yes

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4. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: (No Response)

Reviewer #2: Yes

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5. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: (No Response)

Reviewer #2: Yes

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6. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: (No Response)

Reviewer #2: The authors thoroughly addressed the comments from the first review cycle. In particular, the authors added appropriate notes of caution regarding the scope of this data and the conclusions that can be drawn from a small sample size. The writing was clear and correct and the tables were well formatted.

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7. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy.

Reviewer #1: No

Reviewer #2: No