Adherence to the eat-lancet planetary health diet and sustainability impacts of the Swiss diet

Abstract

Purpose: Diets low in quality represent a large risk for global mortality, morbidity, and environmental deterioration. In 2019, the EAT-Lancet commission published a universal reference diet, the 'planetary health diet' (PHD), focusing on human health and sustainability. We aimed to compare the average Swiss diet, four Swiss dietary patterns, and the sex- and language-specific dietary habits with the PHD with respect to adherence and sustainability.

Methods: Data of the cross-sectional population-based National Nutrition Survey menuCH (2014-2015, n = 2057) were used. Food consumption was assessed with 24-hours dietary recalls. Using the multiple source method, the usual dietary intake was determined. Sustainability impacts were examined by determining Greenhouse Gas emissions, total land and grassland use, the Social Hotspots Index, and diet's costs. Adherence and sustainability of the Swiss diet were analyzed descriptively.

Results: Participants consumed on average more red meat, dairy products, and added sugar and less whole grains, vegetables, legumes, nuts, and unsaturated fats than recommended by the PHD. None or few of the participants adhered to the whole grains (0.0%), legumes (0.0%), and nuts (5.1%) recommendations, whereas nearly all adhered to the tubers and starchy vegetables (97.7%) and saturated fats (99.9%) recommendations. Overall, diets low in animal-source products tended to have reduced Greenhouse Gas emissions and land use, whereas diets high in fruits and vegetables tended to have higher costs and risks of adverse social impacts. In the subgroup analyses, closer adherence to the PHD was seen among females and among participants following the Prudent dietary pattern, while the differences in sustainability impacts were generally small among subgroups.

Conclusion: A dietary shift decreasing consumption of animal-based protein sources and increasing consumption of plant-based foods would be beneficial for Swiss residents' health and lower the environmental footprint of the average Swiss diet. Policy measures should incentivize this dietary shift towards a healthier and more sustainable diet, especially among males and individuals following a traditional or Western dietary pattern, as they have the highest potential for improvement.

Keywords: Diet quality; EAT-Lancet; Planetary health diet; Sustainability; Switzerland; menuCH.