Review Reports - Healthy and Sustainable Diet Index: Development, Application and Evaluation Using Image-Based Food Records

Round 1

Reviewer 1 Report

This is a very interesting study which strives to address a research gap; specifically providing a tool that measures not just healthiness of consumption patterns but sustainability of eating patterns. However, I think the authors need to better explain their process for developing the tool—especially with regard to how they scored sustainability of dietary patterns. More details about these thoughts follow. In addition, the finding that individuals with higher H&S scores who use supplements appears to be a flaw in the tool. Suggest this be addressed as a limitation and the need to add vitamin supplements to the tool with a low score an emerging theme.

Abstract: The summary does not integrate the sustainability measure of the tool. The health metrics are used in other tool, so the sustainability aspect is important to highlight.

Line 24: Change “The aim was to…” to “The aim of this study was to…”

Lines 25-26. The HSDI has 12 components—why are only 4 listed? Or are there 4 categories with a total of 12 items? This is unclear.

Line 63: Suggest adding a few sentences about some of the existing concepts that are used to define a H&S diet, especially with regard to what you incorporated into the HSDI. For example, how did you score eating local vs. eating foods that were transported across various amounts of miles?

“Diet quality indices (DQI) reflect dietary patterns, adherence to dietary guidelines in populations over time, association of dietary intakes with health outcomes, and inform nutrition messages, research, and policy.”

Line 86: Add “s” to DQI—DQIs.

Line 89: Change “using dietary intake data collected using FFQ [19, 20] and repeated 24HR [21]. to “using dietary intake data collected via FFQ [19, 20] and repeated 24HR recall [21].”

Line 95: Only define mFR^TM on first mention in the paper.

Lines 106-136: The explanation of how the HSDI was “theoretically derived” HSDI is confusing. Suggest doing a heavy substantial edit to better explain the steps taken.

Line 108: Only define H&S on first mention in the paper.

Lines 251-253: This finding appears to suggest a flaw in the HSDI. Wouldn’t intake of food be weighted higher than someone who relied on vitamin supplements? I would expect supplements to fall into a low sustainability category—they require manufacturing, packaging, and shipping.

Lines 273-289: See note above re lines 251-253 and at top of review.

Line 292-292: This is where the tool doesn’t take into consideration supplement usage.

Line 314: Change plural females to singular female.

Line 335-335. For example, add supplements as low sustainable choice.

Author Response

Reviewer comments and author responses

Healthy and Sustainable Diet Index: development, application and evaluation using image-based food records

The following responses were constructed on behalf of all authors:

Amelia J Harray, Carol J Boushey, Christina M Pollard, Satvinder S Dhaliwal, Syed Aqif Mukhtar, Edward J Delp, and Deborah A Kerr.

Reviewer 1

The authors wish to thank Reviewer 1 for their constructive and insightful review of the manuscript. The comments and suggested changes have been responded to below and the authors believe this feedback has both strengthened and clarified the methodology and results found. Thank you.

The finding that individuals with higher H&S scores who use supplements appears to be a flaw in the tool. Suggest this be addressed as a limitation and the need to add vitamin supplements to the tool with a low score an emerging theme.

We wish to address this point as we would argue that this is not a flaw within the diet quality tool. Dietary indexes are food-based with the purpose to assess adherence to dietary guidelines and specific dietary patterns. This index addresses a novel aspect of sustainability and, due to additional questions asked about supplements, demonstrates an overlap between the ‘worried well’ and suggests those who are worried about nutrition and can afford and access supplements are those who generally do not need them. We would agree with the reviewer that it is certainly important to capture vitamin supplement use, either in a questionnaire or in future iterations as part of the mobile food record. To help address this, text has been added to the future directions section of the manuscript, as below:

Line 399: “The future directions of this research could amend the mFR^TM to collect additional information from participants, such as the assessment of nutritional supplement use through images and prompts to ask whether their food waste and packaging was put into landfill, recycling or composted.”

Abstract: The summary does not integrate the sustainability measure of the tool. Th health metrics are used in other tool, so the sustainability aspect is important to highlight.

The authors thank the reviewer for this suggestion. We agree that the environmental sustainability aspect makes this tool unique. The following text has been added to the abstract:

Line 25: “The HSDI incorporates 12 items within five categories related to environmental sustainability...”

Line 24: Change “The aim was to…” to “The aim of this study was to…”

Thank you. This has been corrected in the abstract and now reads as:

Line 24: “The aim of this study was to develop..”

Lines 25-26. The HSDI has 12 components—why are only 4 listed? Or are there 4 categories with a total of 12 items? This is unclear.

The following text has been changed as per your suggestion of 12 items within five broader categories.

Line 25: “The HSDI uses 12 components within five categories related to environmental sustainability: animal-based foods; seasonal fruits and vegetables; ultra-processed energy-dense nutrient-poor foods; packaged foods and; food waste.”

The proposed HSDI did not incorporate all aspects of dietary behaviours that are aligned with the definition of a healthy and sustainable diet, including food miles. As the proposed HSDI tool used images to assess healthy and sustainable dietary behaviours, the selection of healthy and sustainable behaviours was confined to those that could be objectively assessed from food and beverage images using the mobile food record. For example, if someone purchased a mixed meal out of the home, the tool could not measure where the meat or grains originated from. The justification for choosing the dietary behaviours in the HSDI were outlined in greater detail in the protocol paper for the present study:

Harray, A., Boushey, C., Pollard, C., Delp, E., Ahmad, Z., Dhaliwal, S., … Kerr, D. (2015). A Novel Dietary Assessment Method to Measure a Healthy and Sustainable Diet Using the Mobile Food Record: Protocol and Methodology. Nutrients, 7(7), 5375–5395. https://doi.org/10.3390/NU7075226

Lines 84-86: Recommend rephrasing “Diet quality indices (DQI) reflect dietary patterns and adherence to dietary guidelines in populations over time and are associated health outcomes and are used to target nutrition messages and inform research and policy.” To “Diet quality indices (DQI) reflect dietary patterns, adherence to dietary guidelines in populations over time, association of dietary intakes with health outcomes, and inform nutrition messages, research, and policy.”

The authors thank the reviewer for this suggestion as it makes the sentence much easier to follow. The sentence now reads as:

Line 95: “Diet quality indices (DQI) reflect dietary patterns, adherence to dietary guidelines in populations over time, association of dietary intakes with health outcomes, and inform nutrition messages, research, and policy.”

Line 86: Add “s” to DQI—DQIs.

This has been corrected and now reads:

Line 97: “A strength of DQIs is that they consider the multidimensional nature..”

Line 89: Change “using dietary intake data collected using FFQ [19, 20] and repeated 24HR [21]. to “using dietary intake data collected via FFQ [19, 20] and repeated 24HR recall [21].”

The sentence has been changed to incorporate the feedback and now reads:

Line 100: “..using dietary intake data collected via FFQ [19, 20] and repeated 24HR recall..”

Line 95: Only define mFR^TMon first mention in the paper.

This has now been corrected and reads as:

Line 114: “..dietary intake using images captured using the mFR^TM”

Lines 106-136: The explanation of how the HSDI was “theoretically derived” HSDI is confusing. Suggest doing a heavy substantial edit to better explain the steps taken.

The authors appreciate this comment and thank the reviewer for the opportunity to clarify the important point about the HSDI being a theoretically derived index. Additional explanations and examples have been added to the methods section of the manuscript to help clarify what is meant by theoretically derived index and how it relates to the scoring system for the HSDI. The additions are:

Line 140: “The theoretically driven HSDI contains twelve components related to H&S dietary behaviours. The items chosen to be included in any diet quality index are a compromise between what information is available and what information is practical to include, which is often driven by the dietary assessment method used to collect the data. Therefore, deciding on the dietary components included and excluded involves an element of researcher subjectivity. Details explaining greater detail of the components included in the HSDI have been described by the authors previously [8].”

Line 162: “For example, ultra-processed EDNP foods and beverages affect health (contributing excess kilojoules and contributing to chronic disease risk) and the environment (use of water, electricity, transport, packaging and disposal). Therefore, these foods and beverages were given a maximum weighting of ten points each. Another example is food waste, which has a direct negative impact on the environment (resources used to dispose of waste and landfill) and a potential influence on health as fresh fruit and vegetables are perishable and often thrown away, creating a barrier for purchase and consumption. However, due to limited evidence on the latter, food waste was assigned a maximum of five points (for an average of ≤10% of edible plate waste over the 4-day mFR).”

Line 108: Only define H&S on first mention in the paper.

The abbreviation meaning has been removed and now reads as

Line 127: “used to assess individual H&S dietary behaviours..”

The authors agree that vitamin supplement use is environmentally unsustainable due to the high level

of processing, packaging and transport. However, it has previously been shown that people who

regularly take vitamin and mineral supplements are more likely to have positive health behaviours,

compared to those who do not take supplements – see Balluz, L.S., C.A. Okoro, B.A. Bowman, M.K.

Serdula, and A.H. Mokdad, Vitamin or supplement use among adults,behavioral risk factor surveillance

system, 13 states, 2001. Public Health Reports, 2005. 120(2): p. 117-23.

This concept of the ‘worried well’ suggests those who are worried about nutrition and can afford and access supplements are those who generally do not need them. The results from the present manuscript support this concept, as participants who reported taking supplements had a higher HSDI score.

An important point the authors would like to highlight is that participants’ supplement use was not assessed through images for the present study, therefore, volumes and frequencies of consumption were not assessed. The assessment method of supplement use has been added to this section of the manuscript, as below.

Line 271: “People who reported taking vitamin supplements in the self-reported written questionnaire were significantly more likely to have a higher HSDI score than those who did not (p< 0.005).

Lines 273-289: See note above re lines 251-253 and at top of review.

Thanks for highlighting this section presenting the results found related to supplements use and the relationship with the HSDI score. Please see the authors’ response to the comment above for line 251-253. No changes have been made to the results presenting in this specific section.

Line 292-292: This is where the tool doesn’t take into consideration supplement usage.

Thank you for highlighting this point. In the present study, vitamin supplement use was assessed using a written questionnaire, not using images with the mobile food record. Supplement use is not routinely captured in traditional dietary assessment tools that focus on food and beverage intake. The dietary behaviours related to environmental sustainability included in the HSDI, such as the ruminant animal intake and edible plate waste, were all assessed using the mobile food record. The authors’ agree that this would strengthen the tool and have added the following test into the limitation section.

Line 314: Change plural females to singular female.

Thank you. This has been corrected and now reads

Line 334: “The study sample was predominantly female…”

Line 335-335. For example, add supplements as low sustainable choice.

The authors have considered this suggestion in depth and believe the examples of supplements as a low sustainable choice would be better suited to the section on future directions. There are many examples that could have been given as a low sustainable choice and the authors believe the two examples of individually packaged food and food waste are well suited to this section. The authors agree the addition of the assessment of supplements would strengthen this tool and therefore, have added supplements as a key dietary behaviour to assess in future studies. Please see addition below:

Line 382: “Future research involving the application of the HSDI to a larger more diverse sample, the collection of markers of health outcomes (such as blood lipid profiles as a risk factor for cardiovascular disease), and images of additional dietary behaviours, such as the use of nutritional supplements, will strengthen the evaluation of the index.”

Reviewer 2 Report

This is a well written manuscript - concise yet with sufficient detail to allow the reader to understand exactly what the study entailed. I have several minor points that I would like to see addressed.

Within the abstract it states “12 individual components:” then goes on to list 4 categories - be careful to avoid confusion.

Within the introduction, it might be helpful to provide an example of how sustainable diets benefit the environment for those less familiar with the climate change literature – e.g., livestock farming? Plastic production for processed foods?

I am unclear why “individually packaged healthy foods and beverages has a max point of 10 – when it seems that greater consumption here is bad for the environment only (and good for health)? Why is it not a max of 5?

The statistical analyses are well described and the results (and tables) nicely presented and interpreted.

Author Response

Reviewer comments and author responses

Healthy and Sustainable Diet Index: development, application and evaluation using image-based food records

The following responses were constructed on behalf of all authors:

Amelia J Harray, Carol J Boushey, Christina M Pollard, Satvinder S Dhaliwal, Syed Aqif Mukhtar, Edward J Delp, and Deborah A Kerr.

Reviewer 2

We wish to thank Reviewer 2 for their insightful and constructive comments to help strengthen the manuscript. Please see the authors’ responses to the comments below.

Within the abstract it states “12 individual components:” then goes on to list 4 categories - be careful to avoid confusion.

This section of the abstract has been edited within the tight word limit and now reads:

Thank you for the opportunity to clarify this important point for readers less familiar with the literature. The following sentence has been added to the introduction.

Line 53: “By adopting more environmentally sustainable dietary behaviours, such as shifting to more plant-based proteins, people can support sustainable food systems and reduce the impact of dietary patterns on the climate [3].”

The authors wish to thank the reviewer for this insightful and well thought out comment. Individually packaged healthy and EDNP foods and beverages were separated as items in the HSDI due to the inherent differences on health. The Reviewer is absolutely correct in stating that there is evidence for both the negative impact of packaging and the positive impact on health, and the authors would like to clarify that a higher HSDI score indicates higher adherence to a healthy and sustainable diet. Therefore, the authors have allocated a higher weighting to the behaviour of consuming healthy individually packaged foods (10 points) opposed to EDNP individually packaged foods (5 points), as this behaviour aligns more closely with a healthy and sustainable diet.

The authors would like to comment that tweaks to the scoring system required application and refinement in a future study and this will be an opportunity to revaluate the scientific evidence and geographically specific environmental data.

No changes to the manuscript have been made as a result of this specific comment.

The statistical analyses are well described and the results (and tables) nicely presented and interpreted.

Many thanks for this feedback.