Thanks for posting this interesting paper. As far as I understand, from reading it, the paper shows that diet related GHGs in Brazil have increased by 21% in the last 35 years, and most of this increase results from the increases in UPF consumption. However, by totting up the figures you provide in the paper in Table 1 there has also been an increase in overall calorie intakes - also of about 20% - you don’t discuss this explicitly in your paper, unless I missed it.
I am afraid I don’t know enough about the food security situation in Brazil over the last 35 years but I was under the impression that it has faced substantial food insecurity, and it has put in place policies to tackle it, such as the Zero Hunger initiative, with some success. So a consequence of a strategy to address hunger would be that overall calorie intakes would increase. Of course I am well aware that increases in calories are not the only thing that’s needed - dietary quality is of paramount importance - and I’m also aware that Brazil now faces triple burdens of ongoing hunger which coexist with obesity and micronutrient deficiencies. Increased calorie intake does not necessarily mean better nutrition and the rise in UPF consumption is extremely concerning in this respect.
However, I would have been interested in a counterfactual analysis which explored what the environmental impacts of a successful strategy to address hunger and malnutrition might have been based on assumed increases in access to, availabilty and consumption of unprocessed and minimally processed foods, as defined by the NOVA system. Otherwise the only conclusion I can draw from this paper is that as calorie intakes rise, so do environmental impacts - because more food overall has been produced. Any comments much appreciated!