Future-proof and sustainable healthy diets based on current eating patterns in the Netherlands
Publication in the American Journal of Clinical Nutrition
Food systems have a significant impact on climate change. To keep global warming below 1.5 °C, as recommended by the Intergovernmental Panel on Climate Change (IPCC), eating patterns must change. However, future diets should also satisfy nutritional requirements and respect cultural acceptability and can therefore best be modeled on national level.
Our colleagues Marcelo and Hans investigated together with a group of researchers what a future-proof and sustainable healthy diet could look like for the Netherlands. Their findings are published in the American Journal of Clinical Nutrition.
Urgent need for transition in food systems and diets
Food systems are important contributors to global greenhouse gas emissions (GHGEs), as well as to land occupation and degradation, biodiversity loss, nutrient flow disruption, freshwater depletion, and depletion of fossil fuels. Transitions in food systems and diets are needed to meet the targets of the Paris Agreement or the Intergovernmental Panel on Climate Change (IPCC) report. The recently published EAT-Lancet report describes a global reference diet that considers the health and environmental sustainability aspects of eating patterns. The EAT-lancet researchers concluded that country-specific analyses, while staying in line with their proposed global reference diet, are needed. Several studies tried to define this at national level, using aggregated data based on food balance sheets, which entails much uncertainty.
Future-proof and healthy sustainable diets for the Netherlands
In this study for the Dutch situation we aimed to identify diets that satisfy nutritional requirements, remain below the GHGE targets, and also deviate minimally from the baseline diet among Dutch adults. Quadratic optimization is used to derive the future diets. We calculated per capita food system GHGE targets for 2030 and 2050 designed to limit the global average temperature rise to 1.5°C. The optimized diets comply with different sets of constraints, using forecasted emissions for 2030 and 2050 and different GHGE scenarios. Besides that, we also studied how food-based dietary guidelines (FBDGs) and eating patterns of for instance flexitarians and vegans affected the results. Finally, we considered 3 scenarios focusing on food diversity, acceptability, and interdependency between food production chains.
Results
The baseline diet among Dutch adults did not meet all nutritional requirements, it was for instance too high in energy (kcal), saturated fat and too low in fiber and iron. In the study, the solutions for all scenarios attempted to correct these nutritional inadequacies.
We show that it is possible to meet both the GHGE targets and nutritional requirements. However, large dietary shifts are needed for very strict GHGE targets, which might not be acceptable/ feasible. Moreover, with vegetarian and/ or vegan eating patterns fortification and/or supplementation with DHA and EPA, vitamin B12 and calcium might be required.
Future diets should contain less meat, especially beef, and more plant-based food products. To achieve future-proof and healthy sustainable diets reduction of the following food products are needed: beef, pork, poultry, cheese, butter, and snacks. At the same time for the following food products an increase is required: legumes, fish and shellfish, peanuts, tree nuts, vegetables, soy foods, and soy drinks. Dairy products other than cheese, grains, and starches can be consumed in amounts similar to those of the baseline diet. We concluded that modeling acceptable country-level diets, which are healthy and sustainable, is challenging.
We have found multiple solutions for future diets and for different eating patterns, meeting food system GHGE targets and nutritional needs. It is possible to meet nutritional requirements and GHGE targets, however, it is difficult to achieve diverse and acceptable diets with current food product availability.
More research is needed, considering a wider range of environmental indicators; additional aspects such as price, taste, and texture; product reformulation; fortification; and supplementation. Shedding more light on these aspects will enable policy makers and advisory associations to decide on ways to identify acceptable changes and guide the necessary dietary shifts.
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Marcelo Tyszler
If you have questions about this research, or if you are interested in sustainable diets get in touch with Marcelo.