Towards Sustainable Food Systems: Exploring Household Food Waste by Photographic Diary in Relation to Unprocessed, Processed and Ultra-Processed Food

Round 1

Reviewer 1 Report

The article is well written, well argued and supported by a clearly explained empirical study. It uses a food classification system adopted by the United Nations (NOVA) that classifies food according to the degree of processing that brings new insights into household food waste. The limitations of the study are well identified.

Perhaps the text could be illustrated with one or two photographs that were used to collect the information. 

In a future research, the frequency of purchase of these various types of food (processed and unprocessed) and the weight of each of these groups in the total purchases may bring an additional element to understand food waste. 

Author Response

Reviewer 2 Report

Dear authors, thanks for this manuscript. I think that you have a treasure of information in your data material but that can be used much better. Some comments:

p.2, line 62: I seems that one motive for the study is a desire to help people eat better for health reasons by helping them to waste less from NOVA 1 category . However, I miss any support for why people should eat better if they waste less from a specific category. Please explain why you think so. Do you have any references that support this hypothesis? Also, reconsider what the motive is for the study. Is it health motives? Or should you add environmental motives? Think about this. I think that the research question is weak.

p.2 3, line 70: I think edible and inedible should change places?

Table 6 and text: Your finding about low food waste levels in 2-person households should be interpreted with care as most other studies show a linear relationship. We know that the variation between households is large, I guess that this result reflect this. I should not try to speculate in causal relationships but simply observe this anomaly and call for more research. 

Table 3,6,7: change "about this level" to "about median level".´

I miss a comparison of food waste levels from your study with other studies.

I also miss some statistics about the variation within for example 2-person households. 

To sum up, I am a bit dubious about the contribution of this paper. I really missed a more detailed analysis of the photos, you have a lot of great information there that can be explored. We really need more detailed information about what kind of food that is wasted and why. I recommend to use your material and identify some specific food items where you can identify more specific actions to help people waste these food items less. in my view, the results of the present paper is too shallow to be of practical use. 

Is it really worth - in practical work - to identify university educated people - or to exclude 2-person households - in interventions? What kind of intervention should benefit from this extra work? My advice in forthcoming research is to talk to people that are involved in such projects. Too much of academic studies are of no use for the society. I understand that you are a PhD, so no blame - just some thoughts to improve your skills. Wish you all luck in your forthcoming work!

Author Response

Please see the attachment

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Dear authors,

thanks for your revised version of the manuscript. I think that you have used my most of my comments and improved the manuscript - great so. I do however have one objection and one general comment.

Objection. I still don't think that you handle the result for 2-person households properly. As you know, statistical significance do not tell us that the result is true, only the likelihood that it is. Your result may still be a result of randomness variation. As the majority of earlier research contradict your findings I don't think that it is scientifically correct to interpret the result as you do. You have added some comments but the original text is still there in many places, it is clear that you still interpret your result as true rather than a possible artifact (for example, page 12 line 402). I recommend to rewrite your text about this matter, not only add some comments to please the reviewer ;). 

General remark. To be honest, I am still doubtful about the contribution of this paper, see my remarks in the original review. However, I have seen published paper with less contribution, so ok. However, I you want to make real contribution to the society I recommend to think more about what make difference int world. 

Author Response

"Please see the attachment." 

Author Response File: Author Response.pdf