Review Reports - Mapping Obesogenic Food Environments in South Africa and Ghana: Correlations and Contradictions

Round 1

Reviewer 1 Report

This article examines the relationship between household food consumption and neighbourhood food availability in two urban areas of Africa (Khayelitsha, South Africa; Ahodwo, Ghana). Although this paper is very interesting, I found it quite difficult to follow/confusing in many areas.

General Comments:

-There is no indication about ethics approval for this study. This must be listed for readers as you collected survey data from research participants.

-When were the data collected for this study? This is not clear.

-There is no information on the development of the survey used to survey households or food outlets. How were the surveys developed etc.? Were they pilot tested etc? This needs to be clarified for readers. (You may also want to include a copy of the surveys used in an Appendix for readers). Also, who in the household completed the survey? How were the households chosen?

-I felt like there were several missing details about the data collection procedures (especially after what was said in lines 506-509). I know that enumerators were used, but there are several missing details about this process. Please provide more details. Also, what was the training provided to the enumerators?

-Why were nuts and seeds not captured as a protective food? Why is brown bread considered a risky food? In North America, this would generally be considered protective.

-You should list early in the results section text how many households participated, and what was the response rate. You should also list the response rate for the food retailers and how many food retailers completed the survey.

-In Table 4, I am a bit confused about the wording for the RI 0 foods especially around low risk groups. What is meant by low risk foods here? I am a bit confused here. Please clarify. I am also assuming these stores do not stock a lot of high risk foods. Perhaps this should be mentioned.

-There is no mention about types of softwares used to conduct your analyses. Please list.

-The limitation section (1.2) seems both in place and out of place in this part of the manuscript. Limitations usually go in the discussion section. Also, how many food outlets in Ahodwo refused to participate?

-In your analyses, why are cooked, fresh, and fried/stir fry vegetables separated?

-The numbers in Figures 7 and 8 are not clear. I am not sure what they mean.

-There are capitalization errors in the text, tables, and figures. Please correct. There are also several spacing errors that need to be corrected.

-There are several abbreviations throughout the manuscript (including in the Tables) that need to be spelled out especially for readers that may be less familiar with this area. Also, please ensure that the abbreviation is placed at the first time the word is mentioned.

-Ensure that your sentences are short and concise to make it easier for readers to follow.

Line-by-Line Comments:

-Lines 5-6: May want to add "food" somewhere in this sentence.

-Lines 8-9: Sentence is awkward.

-Line 11: K and A are unclear

-Line 12: rK and rA are unclear

-Lines 13-16: Sentence is awkward.

-Line 26: You mention sustainable development goals - whose sustainable development goals? This should be clarified for readers.

-Line 36: What is meant by "especially advanced"?

-Lines 36-43: Sentences in this section could be made much clearer for readers.

-Lines 45-46: Do you mean that individuals in the same household can have stunting and obesity?

-Line 47: Deprivation of what?

-Line 51: What are examples of cheaper foods you are thinking of here?

-Line 62: What are examples of supplementary foods you are thinking of here?

-Lines 84-88: A paragraph should not be a single sentence. Please revise.

-Line 85: Potato chips are a type of fried potatoes. Please revise.

-Line 101: Should fresh be eliminated here? Are cooked vegetables/fruit not beneficial as well?

-Line 108: I was not familiar with the NOVA framework (and other readers may not be as well). I suggest providing a bit more information about their categories for readers.

-Line 122: What do you mean by "ultra-processed food have grown" - this is unclear.

-Lines 198-199: Sentence is awkward.

-Lines 237-238: Sentence is awkward and does not fit in with the rest of the paragraph.

-Line 239: Should not end a sentence with "are"

-Line 241: What do you mean by standardized?

-Line 271: I find this sentence a bit confusing.

-Lines 272-274: Is this for food outlet data or household data? Please clarify.

-Line 274-276: I do not understand this sentence.

-Line 315: Move "(unquantified)" to after foods

-Lines 323-330: I find these sentences confusing. Please revise. An example might be helpful to understand how these cut offs work.

-Line 330: May want to start a new paragraph when talking about the food retailers to improve clarity.

-Line 358-359: Which city were these results?

-Line 370: What type of vegetables?

-Line 376: Eggs are not listed in the graph. ?Remove

-Line 380: Is "reflected" the correct word here?

-Line 384: I am unsure what is meant by "The proportional distribution is similar in both sites"

-Lines 384-389: I am confused with these sentences.

-Line 432: Should this be a start of a new section as it is a summary of the results?

-Line 500: Remove "("

-Lines 506-509: Sentence is awkward. Please revise.

-Line 523: Does your study confirm this?

Author Response

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Many thanks for the detauiled comments, which have enabled us to significantly improve our draft.

-There is no indication about ethics approval for this study. This must be listed for readers as you collected survey data from research participants.

Response:Amended - “Ethics clearance was obtained in South Africa from the University of the Western Cape research ethics council (BM17/8/20) and in Ghana from the Centre for Scientific and Industrial Research (CSI: RPN 011/CSIR-IRB/2017).“

-When were the data collected for this study? This is not clear.

Amended

Amended.“Digital survey instruments utilising the ODK smartphone survey app were developed in a consultative process involving the entire interdisciplinary research team. The instrument incorporated standardised survey instruments such as the Lived Poverty Index \cite{mattes_2009} as well as the adapted PURE food frequency questionnaire incorporating the NOVA classification framework. Surveys were additionally reviewed and validated by enumerators as part of an iterative training process including several workshops to ensure clarity and consistency of comprehension. The instrument was pilot-tested with a small sub-sample of respondents to further assess comprehension and time required. “

Amended.“Data were gathered between September and November 2017. Enumerators walked along the roads identified in the sample frame and selected residential properties in the Khayelitsha sampling frame on a 1 in 7 ratio, and in Ahodwo on a 1 in 5 ratio. Enumerators interviewed the household member most knowledgeable about food purchasing and consumption. 327 Khayelitsha households and 309 Ahodwo households participated in the survey, with response rates of 91\% and 97\% respectively. Enumerators sought to interview all food outlets within the sample frame. ” See previous comment re enumerator training.

-Why were nuts and seeds not captured as a protective food? Why is brown bread considered a risky food? In North America, this would generally be considered protective.

Amended - “Both white and brown bread in both sites were classified as ultra-processed food due to the typically high-volume, industrial Chorleywood production process involved which results in just slightly more fibre in the brown bread, though otherwise almost identical with white bread. Nuts and seeds were not included as review of brand information showed that these were typically peanuts with high salt and added oil content which arguably offset possible nutritional benefits.”

Amended: “In Khayelitsha, 327 households participated in the survey and 309 households in Ahodwo. Response rates were 91\% and 97\% respectively. 407 outlets were surveyed in Ahodwo, 83 in Khayelitsha. However, the outlet response rate in Khayelitsha was low (53\%), possibly due to mistrust related to recent xenophobic persecution of foreign-owned informal outlets in South Africa \cite{gastrow_2018} and absence of shop-owners. By contrast, 100\% of Ahodwo retailers agreed to participate in the study.”

Amended to clarify. “Low risk foods include mainly NOVA class one (whole) staples such as maize meal, rice, potatoes, meat, eggs or class two (refined ingredients such as oil).” & “Outlets marked as low-risk would stock few ultra-processed food types, but mostly the low-risk, minimally-processed foods mentioned above.”

-There is no mention about types of softwares used to conduct your analyses. Please list.

Amended. Most analysis entailed descriptive statistics which were generated using custom-coded google sheets functions: “Customised analysis frameworks for both household and neighbourhood scales were developed on google sheets. Standard spreadsheet functions were used to recode data to generate composite indices of obesogenic and protective food provision and consumption.”

-What type of statistical analyses did you use? (e.g., type of correlations, test used for pairwise comparisons) What software did you use? This is not well described. There should be a section in the methods section to describe this information. Amended:“These were analysed using descriptive statistics such as counts and frequency distributions. Crosstabulations were done to compare dietary risk class distribution between Ahodwo and Khayelitsha samples, internally between income-deprived and non-deprived households in each area sample, and between outlet risk distribution in both sites. Significance of distribution patterns were tested using Pearson's chi-square test. Finally, the correlation (r) between provision and consumption risk classes was tested for both sites.”

Amended – moved. All Ahodwo outlets participated.

-When discussing Figures 3, 4, 5, and 6, be sure to use the same terminology in the text as in the graphs to make it easier for readers to follow. Also for Figures 3 and 4, you should have a title for the x axis. AmendedFor figures 5 and 6, I am unclear of the numbers at the end of the graph (e.g., 302, 230, 259 etc.) This should be clarified for readers. Amended.The numbers at the end of the graph represent the totals for each item to ensure that the proportional representation does not mask important differences in total counts. This has been reflected in the captions.

-In your analyses, why are cooked, fresh, and fried/stir fry vegetables separated? Data were gathered to reflect different food preparation practices, and this has not been re-coded to retain a more nuanced representation of these.

-The numbers in Figures 7 and 8 are not clear. I am not sure what they mean. Amended in caption– they reflect category counts.

-There are capitalization errors in the text, tables, and figures. Please correct. There are also several spacing errors that need to be corrected. Amended where apparent.

-Ensure that your sentences are short and concise to make it easier for readers to follow. Amended – various sections indicated in your line-by-line comments have been simplified and broken up int shorter sentences to facilitate reading.

-Lines 5-6: May want to add "food" somewhere in this sentence.

Done

-Lines 8-9: Sentence is awkward. Amended

-Line 11: K and A are unclear Amended

-Line 12: rK and rA are unclear Amended

-Lines 13-16: Sentence is awkward. Amended

-Line 26: You mention sustainable development goals - whose sustainable development goals? This should be clarified for readers.Amendedwith reference to the United Nations

-Line 36: What is meant by "especially advanced"? Amended-“This transition has been particularly rapid in Sub-Saharan Africa \cite{vorster_2011}\cite{steyn_2014}, with nutritional change, obesity and NCDs in South Africa and Ghana especially advanced(Abrahams 2011, Bosu 2015).”

-Lines 36-43: Sentences in this section could be made much clearer for readers. Amended

-Lines 45-46: Do you mean that individuals in the same household can have stunting and obesity?Amended – no, usually other individuals in the same household.

-Line 47: Deprivation of what?Amended with reference to multiple deprivation and lived poverty.

-Line 51: What are examples of cheaper foods you are thinking of here? Amended - “substitute cheaper foods such as starchy staples, sugar and oils.”

-Line 62: What are examples of supplementary foods you are thinking of here?

Amended: cutting back on supplementary foods such as rice to enable consumption of primary staples like maize or yam

-Lines 84-88: A paragraph should not be a single sentence. Please revise.Amended

-Line 85: Potato chips are a type of fried potatoes. Please revise. Amended to specify ultra-processed crisps, which are nutritionally and economically different from fried (fresh) potatoes.

-Line 101: Should fresh be eliminated here? Are cooked vegetables/fruit not beneficial as well? Amended

-Line 108: I was not familiar with the NOVA framework (and other readers may not be as well). I suggest providing a bit more information about their categories for readers. Amended: “The NOVA framework classifies food according to four types depending on the nature, purpose and extent of processing. Type one foods are whole and minimally-processed foods, type two are ingredients such as oil, butter or sugar derived from whole foods, type three are combinations of types one and two, frequently used to preserve food. Type four, ultra-processed foods, are typically industrial mass-products composed of multiple refined ingredients including sugar, cheap starches and oils, salt and various other additives which increase shelf life or alter the flavour, texture or colour of food. Examples include processed cheese, processed meats, confectionery, instant noodles, most breakfast cereals, and sugar-sweetened beverages. Detailed studies using this framework have been conducted in several countries. These studies have revealed a direct association between consumption of ultra-processed products and weight gain and increased risk for various NCDs”

-Line 122: What do you mean by "ultra-processed food have grown" - this is unclear. Amended

-Lines 198-199: Sentence is awkward. Amended

-Lines 237-238: Sentence is awkward and does not fit in with the rest of the paragraph. Amended: “The underlying interest is to understand to what extent food outlets in the local food geography promote the consumption of obesogenic foods and of healthier food options.”

-Line 239: Should not end a sentence with "are" Amended: “The second line of inquiry considers the policy, planning and governance implications of these findings.”

-Line 241: What do you mean by standardized? Removed - confusing and unnecessary term

-Line 271: I find this sentence a bit confusing. Amended

-Lines 272-274: Is this for food outlet data or household data? Please clarify.

-Line 274-276: I do not understand this sentence. Amended: “In some cases, georeferences could not be collected due to technical errors or because enumerators considered the use of smartphones unsafe. In these cases, georeferences were randomly allocated based on the approximate location of the sample. “

-Line 315: Move "(unquantified)" to after foods Amended:“The household questionnaire recorded the frequency of consumption of various foods but not the quantity. Consequently, this framework considers reflects both frequency and diversity, but cannot predict dietary adequacy without further validation. “

-Lines 323-330: I find these sentences confusing. Please revise. An example might be helpful to understand how these cut offs work. Amended: “A frequency cut-off was set to establish whether a given food is consumed frequently enough to contribute to obesity risk or prevention. Two or more occasions of consumption per week was selected as reflecting frequent consumption for risky foods, five per week for protective foods, as these need to be consumed at a high frequency in order to provide protective benefit. The obesogenic cutoff is set low in order to ensure the index is sensitive to the aggregate effects of occasional consumption of different obesogenic foods. A second cutoff was set to reflect the number of risky or protective foods exceeding the first (frequency) cutoff. As there is a larger number of food types in the risky category than in the protective category, this class has a higher cutoff (4) for number of foods. For example, if a household reported consuming processed meat three times a week, industrial bread five times a week, cookies twice, and sugar-sweetened beverages every day, they would have reached the cutoff for intake of obesogenic foods. If they also ate fruit only once or twice a week, cooked vegetables and legumes five times a week, and no other protective foodds, the diet would not reach the minimum cutoff to be classed protective.

-Line 330: May want to start a new paragraph when talking about the food retailers to improve clarity. Amended

-Lines 355-359: It would be helpful to include this information in a table for readers. I am also a bit confused by these results. For example, what does high risk diets mean? Does it mean they consumed lots of high risk foods with or without protective foods or does it mean they consumed high risk foods with a low consumption of protective foods? This is unclear. Please clarify throughout the manuscript. Amended: “The findings show that 71\% of Khayelitsha respondents reported household diets that met or exceeded the cutoffs for obesogenic foods, while only 16\% reported consuming diets meeting or exceeding cutoffs for protective food. In Ahodwo, the pattern is different, with approximately one quarter of households surveyed (26\%) consuming diets high in obesogenic foods, and only 23\% reporting frequent and varied consumption of protective food. Two thirds of respondent households reported consuming low risk diets lacking in protective foods. In both samples, there is a notable dearth of protective food consumption.”

-Line 358-359: Which city were these results? Amended - Ahodwo

-Line 370: What type of vegetables? Amended - fresh

-Line 376: Eggs are not listed in the graph. ?Remove Amended

-Line 380: Is "reflected" the correct word here? Amended

-Line 384: I am unsure what is meant by "The proportional distribution is similar in both sites"The proportions of the different outlet classes are similar in both sites.

-Lines 384-389: I am confused with these sentences. Amended

-Line 432: Should this be a start of a new section as it is a summary of the results? Amended

-Line 500: Remove "(" Amended

-Lines 506-509: Sentence is awkward. Please revise. Amended

-Line 523: Does your study confirm this? Amended “The present study confirms high levels of purchase and consumption of ultra-processed foods in urban settings of South Africa and Ghana. However, the higher prevalence of obesogenic food consumption in Khayelitsha, especially in comparison with Ahodwo, where poverty is less extreme, calls the generic correlation of obesogenic food consumption with increased incomes into question.”

Reviewer 2 Report

This manuscript details a labour intensive and valuable body of work. Having accepted the review and seeing the full manuscript, In my own field, I would judge that the information presented is too lengthy and not set within a broad enough context to be digested (it feels more like a funder report) and is not formatted according to journal article conventions (e.g. lengthy introduction with multiple subsections, limitations section in the methods, etc). However, I would like to reiterate that other reviewers who work in international development may reach a different verdict.

Author Response

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Thank you for your comments, which have helped us refine the paper significantly. Below are point-by-point responses.

The article attempts to draw linkages between different scales of food environment analysis, namely household and neighbourhood, and relate these to broader food systems dynamics (Big Food, Ultra-processing) on the macro-end of the scale, and to obesity on the individual scale. Developing this broad context required a substantial introduction providing readers unfamiliar with the conceptual terrain with a wide overview. The MDPI author guidelines did not stipulate a length restriction.

and not set within a broad enough context to be digested (it feels more like a funder report)

The study actually generated a very broad dataset, of which the present article reveals only a fairly narrow slice. We have attempted to shorten and simplify the text for legibility, but in the brief review period, a substantial shortening was not possible without risking loss of the logic linking the different scales of analysis.

and is not formatted according to journal article conventions (e.g. lengthy introduction with multiple subsections, limitations section in the methods, etc).

The article followed the template provided by MDPI, which stipulates that conceptual framings be included in the first section “introduction”. However, we have shifted the limitations section to the discussion.

However, I would like to reiterate that other reviewers who work in international development may reach a different verdict.

Reviewer 3 Report

Quite an unusual long introduction (L19 - 239).

L26-27: The specific SDGs can be mentioned here i.e SDG 2 and 12

L76-78: The authors cited several references for this sentence which in my opinion a maximum of four references will do

L91-92: Same comment as above

L 395-401: On the income levels, the authors may equally indicate the equivalent amount in Euros

L 550: 'above-mentioned' instead of 'abovementioned'

'e.g.' instead of 'eg'

Under 'Author Contributins': It is probably better to indicate a dash - before the names instead of , after the task carried out e.g. Conceptualization - Florian Kroll, Elizabeth....

Under 3.4. Implications for Planning, Governance and Policy: It will be advisable that the local suppliers of food in both urban sites pool their resources together. The government will then be able to support better value addition through processing that can utilise distributed manufacturing. Such products can then make their ways into the shopping malls for better storage at cold temperature. This will improve food sovereignty in both Khayelitsha and Ahodwo urban sites.

Author Response

Thank you for your comments, which have helped us refine the paper significantly. Below are point-by-point responses.

Quite an unusual long introduction (L19 – 239). This has been edited somewhat to shorten sentence structure. However, the subject matter is complex and includes several key concepts which need discussion in order to contextualise the research approach, methods, and findings.

L26-27: The specific SDGs can be mentioned here i.e SDG 2 and 12 Amended accordingly

L76-78: The authors cited several references for this sentence which in my opinion a maximum of four references will do Amended

L91-92: Same comment as above Amended

L 395-401: On the income levels, the authors may equally indicate the equivalent amount in Euros Amended

L 550: 'above-mentioned' instead of 'abovementioned' Amended

'e.g.' instead of 'eg' Amended

Under 'Author Contributins': It is probably better to indicate a dash - before the names instead of , after the task carried out e.g. Conceptualization - Florian Kroll, Elizabeth.… Amended

Added: “Infrastructure, regulation and social capital development supporting local aggregation and distribution of fresh produce through cold chains, as well as the development of distributed micro-processing facilities may enhance the availability and lower costs of fresh and minimally-produced food.” However, we are not making reference to the issue of food sovereignty in this paper, as this would require introduction and discussion of an additional conceptual frame which would extend the scope significantly.