PONE-D-21-13158

The Editor

South African consumers' perceptions of front-of-package warning labels on unhealthy foods and drinks

PLOS ONE

Dear Dr. Bopape,

Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process.

Associate editor's comments:

In particular, as recommended by reviewer 2, please include a more comprehensive overview of the use of warning labels in your introduction.  For instance, you do not describe pictorial or graphic warning labels as described by Pechey et al. While this publication postdates the conduct of the focus groups, this style of warning label should nevertheless be described and the relative merits discussed.

Pechey, E., N. Clarke, E. Mantzari, A. K. M. Blackwell, K. De-Loyde, R. W. Morris, T. M. Marteau and G. J. Hollands (2020). "Image-and-text health warning labels on alcohol and food: potential effectiveness and acceptability." BMC Public Health 20(1): 376.

Lines 488-498 I think more could be made of the differences between countries regarding consumer shape preferences, as justification for the need to replicate this type of research locally. This finding highlights the importance of having culturally relevant shapes, as shapes are not universally interpreted in the same manner.

Please check the guidelines for reference lists.  Some titles are fully capitalized, while others have only the first word of the title and proper nouns capitalized. You can manage this in Endnote by without having to change the titles of references by editing the output settings. In the bibliography section choose sentence style capitalization in the title capitalization subsection.  Although, recheck the titles carefully as proper nouns such as place names will have had their capitalization removed.

https://journals.plos.org/plosone/s/submission-guidelines#loc-references

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We look forward to receiving your revised manuscript.

Kind regards,

Jane Anne Scott, PhD, MPH Grad Dip Dietetics, BSc

Academic Editor

PLOS ONE

Additional Editor Comments:

Minor corrections

Line 60 Other than when used in reference to grains, i.e. intact grains, the phrase ‘intact foods’ is not commonly used to describe other groups of unprocessed or minimally processed foods.

Lines 69 to 70. This sentence referring to access to ultra-processed foods is not needed in this paragraph justifying the FOPL. You have already linked ultra-processed foods to NCDs in lines 56-58.

Line 129 and elsewhere, data is the plural of datum so should be ‘data were’ collected.

Lines 211-212 presumably the moderator first transcribed the recordings verbatim and THEN translated the data into English where applicable. In which case this sentence should be reordered.

Lines 227-228 The aim of the study does not need to be repeated here.

Line 501 the use of the word thus in this sentence implies that the reason for the preference for black is explained in the first half of the sentence, when in fact the rationale for preferring black is provided in the second half of the sentence. Therefore, suggest rewording as ‘black was deemed more effective’.

Line 511 presumably you mean a white triangle on a black background and NOT a black triangle on a black background

Line 543 should read ultra-processed foods (plural)

Line 544 should read labels (plural)

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[We thank School of Public Health at the University of the Western Cape and the DSI/NRF CoE in Food Security UID 91490) for support.]

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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: Partly

Reviewer #2: Partly

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

Reviewer #1: Yes

Reviewer #2: N/A

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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

Reviewer #2: No

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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

Reviewer #2: 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: Thank you for letting me review this manuscript. This is a topic worthy of discussion since the high prevalence of overweight and obesity. However, there are some comments:

1. In line 150, please add the references after the sentence: "...detailed design brief based on the latest literature"

2. According to the following article (An, 2021), Graphic with health effect labels showed the largest impact on dissuading consumers from choosing them. Why the design of graphic (e.g., graph of health effect, which displays a picture of an obese belly or decayed teeth with relevant descriptions, and graphic with nutrient profile, which displays a picture of sugar added in the drinks with corresponding descriptions) was not used in the label design in this study?

An R, Liu J, Liu R, Barker AR, Figueroa RB, McBride TD. Impact of Sugar-Sweetened Beverage Warning Labels on Consumer Behaviors: A Systematic Review and Meta-Analysis. Am J Prev Med. 2021;60(1):115-126. doi:10.1016/j.amepre.2020.07.003

3. There are lots of mistakes in the reference, please revise the format of the references.

Reviewer #2: The manuscript deals with a relevant topic for public health policy worldwide. The manuscript addresses South African citizens’s perception of warning labels. However, major changes are needed before the manuscript can be considered for publication. Details comments are provided below.

Introduction

- The introduction fails to provide a comprehensive overview of the topic. The authors did not include a thorough analysis of the literature to clearly convey what is known about the topic and what are the knowledge gaps. The authors should include a more detailed analysis of the growing body of evidence around warning labels.

- Considering that the manuscript is focused on warning labels, details on other FOP nutrition labelling schemes is not necessary. The inclusion of Figure 1 is not necessary in the context of the manuscript.

- The contribution of the manuscript should be more clearly presented. How does the manuscript contribute to the literature? Is the contribution related to the specific context (South Africa)?

Objectives

- The authors state that one of the aims of the manuscript was to identify “features that enhance or diminish the effectiveness of a warning label”. However, the design is not appropriate to address this objective. Qualitative research enables to explore a specific topic but cannot be regarded as appropriate to evaluate the effectiveness of a public policy or to identify features that enhance or diminish its effectiveness. The authors could refer to “identify citizens’ views on features that could influence the effectiveness of warnings” or something like that.

Materials and Methods

- How was the number of participants selected?

- Did the authors rely on theoretical sampling for the design of the study?

- How did the authors manage participants’ heterogeneity? Did they conduct focus groups with participants from very different settings? This should be better explained.

- What was the purpose of creating so many warning labels? Do the authors think that participants were actually able to pay attention to the nuances between all the designs?

- Qualitative research is not appropriate to select the most attention grabbing, the most effective or the most likely to influence purchasing behavior. Quantitative research should have been used for this purpose. In addition, the social interactions during focus groups make it not possible to assess individual opinions on the topic.

- The authors should have included the question guide. It is an essential element to evaluate the validity and reliability of qualitative research.

- How did the authors handle the influence of participants’ characteristics on their opinions?

Results

- Additional details are needed in the Results section to more clearly convey the results. I recommend the authors to include quotes in Table 3.

- The authors should be careful about the interpretation of the results. As I have previously mentioned, they are dealing with focus groups and therefore results should be interpreted considering their qualitative nature. Several changes should be made throughout the text.

- I recommend the authors not to refer to “the most understood design features”.

- How could the authors generalize their results to different groups of participants? For example, they stated that “participants from all socio-economic backgrounds” had positive attitudes towards the warnings. They did conduct separate focus groups? Did all participants explicitly stated their opinion?

Discussion

- The flow and clarity of the Discussion section could be improved.

- The authors should rewrite many parts of the discussion where they refer to the comparison of labels and design features considering the type of data they are dealing with. For example, they state “black was more effective”.

- An important point the authors should discuss is related to the contraposition between citizens’ opinions and actual effectiveness of the policy. This is particularly relevant for the discussion, as the authors could encourage other researchers to base policy decisions exclusively on qualitative data.

- As far as I know, the Uruguay nutrition labelling policy entered into force in 2020, so I guess that there are no studies showing changes in expenditure. This should be clarified in line 527, as I think the authors are mixing up an experimental study with the evaluation of policy impact.

- The limitations of the study should be better acknowledged in the paper, as well as suggestions for further research.

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Reviewer #1: Yes: Jianxiu Liu

Reviewer #2: No

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The Editor

South African consumers' perceptions of front-of-package warning labels on unhealthy foods and drinks

PONE-D-21-13158R1

Dear Dr. Bopape,

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.

An invoice for payment will follow shortly after the formal acceptance. To ensure an efficient process, please log into Editorial Manager at http://www.editorialmanager.com/pone/, click the 'Update My Information' link at the top of the page, and double check that your user information is up-to-date. If you have any billing related questions, please contact our Author Billing department directly at authorbilling@plos.org.

If your institution or institutions have a press office, please notify them about your upcoming paper to help maximize its impact. If they’ll be preparing press materials, please inform our press team as soon as possible -- no later than 48 hours after receiving the formal acceptance. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information, please contact onepress@plos.org.

Kind regards,

Jane Anne Scott, PhD, MPH Grad Dip Dietetics, BSc

Academic Editor

PLOS ONE

Additional Editor Comments (optional):

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: Yes

Reviewer #2: Yes

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

Reviewer #1: Yes

Reviewer #2: N/A

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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: Yes

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: Yes

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: The study explores consumers’ perceptions of warning labels and consumers’ views on design features that could influence the effectiveness of a warning label. After the first round of revising, the manuscript improved and can be accepted now.

Reviewer #2: Thank you for addressing all my comments. The manuscript has improved and, in my opinion, can be accepted for publicaiton.

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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