Food recommendations by countries are made for people to follow a healthy diet. Prior simulated research has shown that if the people followed these recommendations, their diets would be healthier and also have a lower carbon footprint. However, the opposite has been shown for the US – if people followed dietary guidelines, the greenhouse emissions increased.
“This anomaly prompted us to investigate how dietary guidelines vary between countries and the consequent implications for greenhouse gas emissions,” commented Diego Rose, corresponding author.
The research team compared the dietary guidelines and food consumption patterns of seven countries – India, Germany, Oman, the Netherlands, Uruguay, Thailand, and the United States.
Findings showed that India’s dietary guidelines had a comparatively low carbon footprint – the recommended diet was associated with the equivalent of 0.86 kg CO2 per day. While the recommended diet of the US was associated with 3.83 kg CO2 per day.
The US carbon footprint was almost 1.2 times that of the Netherlands (2.86 kg CO2 per day) and almost 1.5 times that of Germany (2.25 kg CO2 per day).
Even the US’s vegetarian dietary guidelines (equivalent to 1.80 kg CO2 per day) were still two times India’s, mainly due to the high dairy recommendation.
The broad range of daily recommended amounts for each food group, protein and dairy foods, in particular, was the main difference in the various countries’ dietary guidelines. In addition, which foods were included in each food group also differed.
Brittany Kovacs, lead author, said, “There is great variation in the global warming impacts of these individual foods, which foods people consume and how much of them have an impact on the carbon footprint of dietary guidelines. For instance, beef, mutton, and lamb, in Uruguay, accounts for 31% of protein foods, whereas it is only 16% in Germany. Thus, our calculated greenhouse gas emissions for Uruguay’s protein food recommendation is 53% higher than Germany’s, even though both countries’ quantity recommendations for protein foods as a food group is about the same.”
Rose adds that the US Vegetarian guideline is almost identical to the main US guideline, except for the protein group, which recommends legumes, soy, nuts, seeds, and eggs. This results in an overall carbon footprint that is less than half.
The authors advise that other environmental impacts, like land and water use, should also be considered when evaluating a diet’s overall impact since their study only considers a single environmental impact – greenhouse gas emissions.
Kovacs states, “These findings hold insights for the future development of dietary guidelines and highlight the importance of including sustainability considerations, such as reductions of protein food and dairy recommendations and the inclusion of more plant-based substitutions for animal-based products.”
She adds that including more sustainable yet still health-based considerations into dietary recommendations can influence the larger food and agriculture sector’s environmental impacts across the world.