The Climate Footprint of Diabetic and Gluten-Free Diets in Australia

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Dear Authors,

It was a pleasure to be appointed to review the article entitled “

 The climate footprint of therapeutic Australian diets “ submitted for review in Dietetics.

The idea of this association is very interesting and I consider that is an excellent start in the actual ecosystem conditions.

I have some suggestions:

Lines 1-10- abstract can be shortened, and I strongly recommend a graphical abstract

Lines 75-76- How have you choosed the two pathologies studies? Can you detail the reason for selecting those pathologies?

Line 95- data are from 2011- quite old, I dare to say

Do you have the informed consent? If so, I would like to have a copy of it.

Similarity ratio is too high. Try to decrease at 10-15%

Author Response

Lines 1-10- abstract can be shortened, and I strongly recommend a graphical abstract

The abstract has been slightly amended for brevity. A graphical abstract is now included.

Lines 75-76- How have you choosed the two pathologies studies? Can you detail the reason for selecting those pathologies?

This is outlined in the introduction. However an additional line has been included to give context to this rationale: “We sought to quantify the impact of two common therapeutic dietitians managed by dietitians: the diabetic diet and the gluten free diet .”

Line 95- data are from 2011- quite old, I dare to say

Yes we agree – the data from the most recent Australian Health Survey is not yet available  (due 2025) so we have used what is the most up to date in our context.

Do you have the informed consent? If so, I would like to have a copy of it.

This is not required for this study as it is using publicy available data.

Similarity ratio is too high. Try to decrease at 10-15%

I am unclear what my similarity rating is – however much of the methods is identical to that used in a previous study by our team (DOI:  10.1111/jhn.13204 ) so there may be substantial overlap there.

Reviewer 2 Report

Comments and Suggestions for Authors

Dear Authors,

 

Thank you to give the opportunity to review the manuscripts. It is interesting, I have some suggestions to improve it.

Title:

I will specify the two types of diets that are evaluated (Type 2 diabetes and Coeliac disease) to avoid confusion reading the title.

Abstract:

The sentence "Neither the diet for Coeliac disease nor the diet for Type 2 diabetes were considered climate neutral" could be rephrased for conciseness (e.g., "Both the Coeliac disease and Type 2 diabetes diets had a measurable climate footprint.").

 

Introduction:

The introduction is too long, long paragraphs should be split to improve readability. For example, split and shorten the section on the Paris Agreement and emissions from food production.

 

Material and Methods:

Add as subsection titled “Study Design” to summarize the study as a whole.

GWP* calculator: I have not found a link to the calculator in the references. It should be better explained and include a direct link to the programme.

A section as “Statistical Analysis” should be included, with the description of the statistical analysis used for the description of the variables. In line 169 “A Weighted Chi-squared test was undertaken in SPSS to test for significant differences in CO2e produced by each food group between the four diets.” But I have not seen that in the Results and Discussion.

 

Results:

Statistical Analysis: Clarify the application and significance of the Weighted Chi-squared test.

Expand on unexpected results (e.g., why the gluten-free diet has a higher CO2e than the current Australian diet).

 

Discussion:

I recommend to highlight how this study fills gaps in current research on therapeutic diets and sustainability. Suggest more specific areas for future work, such as validating findings in other demographics or refining the GWP* calculator. Provide more actionable advice for dietitians on how to implement findings

 

Conclusions:

I recommend to reiterate the significance of sustainability in the therapeutic diets and include a final call to action for policymakers, dietitians, and researchers.

 

Best regards,

 

Author Response

Title:

I will specify the two types of diets that are evaluated (Type 2 diabetes and Coeliac disease) to avoid confusion reading the title.

This has now been amended – thank you for the suggestion

Abstract:

The sentence "Neither the diet for Coeliac disease nor the diet for Type 2 diabetes were considered climate neutral" could be rephrased for conciseness (e.g., "Both the Coeliac disease and Type 2 diabetes diets had a measurable climate footprint.").

 This suggestion has been included

Introduction:

The introduction is too long, long paragraphs should be split to improve readability. For example, split and shorten the section on the Paris Agreement and emissions from food production.

 The introduction has now been revised and many paragraphs revised for brevity

Material and Methods:

Add as subsection titled “Study Design” to summarize the study as a whole.

This has now been included

GWP* calculator: I have not found a link to the calculator in the references. It should be better explained and include a direct link to the programme.

Thank you for pointing this omission – we have now included the citation

A section as “Statistical Analysis” should be included, with the description of the statistical analysis used for the description of the variables.

 A new statistical analysis section heading has now been included.

In line 169 “A Weighted Chi-squared test was undertaken in SPSS to test for significant differences in CO2e produced by each food group between the four diets.” But I have not seen that in the Results and Discussion.

Regarding the differences using the weighted chi Square test – the results are included in the results (line 201-202): There were no statistically significant differences in the CO₂e produced by each food group between the four diets analysed (p = 0.67).

Results:

Statistical Analysis: Clarify the application and significance of the Weighted Chi-squared test.

Additional wording has now been included in the statistical analysis section on this.

Expand on unexpected results (e.g., why the gluten-free diet has a higher CO2e than the current Australian diet).

This has now been expanded in the discussion section and we hope that clarifies for the reviewer. It now reads: It was surprising to find the gluten free diet contributed a greater amount of CO₂e per day than the current Australian diet. This appears to be related directly to the high frequency of beef meat consumption (with four main meals per week derived from beef. This is well known to have a high carbon footprint ^{9, 17, 44}. Dairy intake in the gluten free diet was almost double (37% of CO₂e) compared to that of the current Australian diet (17% of CO₂e), with dairy another significant contributor to CO₂e emissions.

 

Discussion:

I recommend to highlight how this study fills gaps in current research on therapeutic diets and sustainability. Suggest more specific areas for future work, such as validating findings in other demographics or refining the GWP* calculator. Provide more actionable advice for dietitians on how to implement findings

 Additions have been included to reflect these comments.

Conclusions:

I recommend to reiterate the significance of sustainability in the therapeutic diets and include a final call to action for policymakers, dietitians, and researchers.

Additional wording has now been included

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

Dear authors

Thanks for responding to my suggestions

Comments on the Quality of English Language

The quality of english language doesn ,t affect the understanding of the scientific content

Author Response

Thank you for the time spent reviewing out paper

Reviewer 2 Report

Comments and Suggestions for Authors

Dear Authors,

Thank you to give the opportunity to review your manuscript.

2.3 Calculation of climate footprint

Line 132 and 135 the references are different to the rest of the text.

Is still unclear how the CO2e was calculated:  

    “Individual food items in grams per day were entered into the GWP* calculator to determine the CO2e. This tool was developed by Ridoutt et al”

 

It should be better described how CO2e was calculated, whether by a specific mathematical formula, included in the manuscript or by a programme, and specified, so that other researchers can reproduce it and arrive at the same results.

 

SimaPro or GaBi: These software tools allow for the integration of GWP and GWP* into their LCA calculations. You could model the climate footprint of specific diets (such as the Australian diet analyzed in the study) using these tools, provided you have access to food-related databases.

OpenLCA: This open-source software can be used with the Agri-footprint or Ecoinvent database to calculate the GWP of different food products and diets. You would need to set up the analysis yourself using relevant dietary data.

CoolFood (WRI): While it doesn’t use GWP* specifically, it provides a carbon footprint calculator that evaluates the impact of various diets and foods on the climate. It could be a good starting point for simpler calculations of dietary carbon footprints.

Customized Excel-based Calculators: Some studies or organizations may provide Excel-based calculators that estimate the GWP of dietary patterns, using simplified models based on the general principles of LCA.

 

2.4 Statistical analysis

“A Weighted Chi-squared test was undertaken in SPSS 32 to test for significant differences in CO2e produced by each food group between the four diets. This type of test is the preferred method for analyzing nominal variables in the form of proportions.”

 

I did not see the Chi-square test in the manuscript. Was a normality test performed to establish whether or not the distribution of the variables was normal?

 

Best regards,

Author Response

Response to review

REVIEWER 2

• Line 132 and 135 the references are different to the rest of the text.

Thank you – this has been corrected

• Is still unclear how the CO2e was calculated:  

    “Individual food items in grams per day were entered into the GWP* calculator to determine the CO2e. This tool was developed by Ridoutt et al”

 It should be better described how CO2e was calculated, whether by a specific mathematical formula, included in the manuscript or by a programme, and specified, so that other researchers can reproduce it and arrive at the same results.

 Thank you for the query. The details of how the previously developed calculator derived CO2 values is beyond the scope of this paper. Readers can refer to the original paper that outlines this (Riddout et al). We have included more details on our calculations and this now reads:

Individual food items in grams per day were entered into the GWP* calculator ⁹ to determine the CO₂e. This tool was developed by Ridoutt et al ⁹. This calculator comprises an excel spreadsheet of 232 Australian foods with C0₂e values for each food. The weight of each food in the meal plan was multiplied by the GWP* CO₂e value to arrive at the final amount of CO₂e produced by each diet.

 

 

2.4 Statistical analysis: “A Weighted Chi-squared test was undertaken in SPSS 32 to test for significant differences in CO2e produced by each food group between the four diets. This type of test is the preferred method for analyzing nominal variables in the form of proportions.”  

I did not see the Chi-square test in the manuscript. Was a normality test performed to establish whether or not the distribution of the variables was normal?

 

Details of the results of the Chi Square test are shown in the revised version lines 202-204: There were no statistically significant differences in the CO₂e produced by each food group between the four diets analysed (p = 0.67)

Regarding normality, this was not required as we examined proportions not continuous data.

 

Author Response File: Author Response.docx

Round 3

Reviewer 2 Report

Comments and Suggestions for Authors

Dear Authors, 

 

Changes have been applied correctly. 

 

Best regards,