Integrating nutrient bioavailability when identifying sustainable diets: How low should we reduce meat consumption?

Abstract

Current public health and environmental issues require identifying dietary changes that both improve nutritional quality and reduce the environmental impact of our diet. A diet optimization approach has been used to assess whether taking into account the bioavailability of nutrients would influence the composition, especially in meat, of more sustainable diets. Two diets as close as possible to the average diet observed in adults and with a reduced environmental impact of at least 30% were obtained: in the first model (NE), compliance with the recommended dietary intakes was imposed for all nutrients; in the second model (NEB), nutritional adequacy was further ensured by taking into account the bioavailability of iron, zinc, protein and vitamin A. Starting from 110 g/d in women's OBS diet (168 g/d for men), total meat quantity decreased by 78% and 67% for women (68% and 66% for men) in NE and NEB diets, respectively. Starting from 36 g/d women's OBS diet (54 g/d for men), ruminant meat quantity dropped severely by 84% and 87% in NE and NEB diets for women (80% and 78% for men). The share of protein of animal origin decreased in the 2 modeled diets, from about 66% in the diets observed to slightly more than 50% in modeled diets. Reducing meat consumption of French adults is thus a necessity to improve diet sustainability, and taking into account nutrient bioavailability does not modify this conclusion.