How to conciliate nutritional and environmental targets of adult diet in France while halving current meat consumption?

•In France, adults consume 124g/day of meats, including poultry and deli meats.•Halving meat consumption is recommended to contribute to the ecological transition.•It is compatible with good nutrition, with no need for supplements,•including a majority (70% of solid weight) of unrefined and minimally processed plant-based foods,•with meats (excluding delimeat), fish or eggs 1 time/day, and dairy maintained. To contribute to the ecological transition, several scenarios recommend reducing by 50% or more the current meat consumption in France. The aim of the present study was to identify which minimum dietary changes would be necessary, in addition to halving meat consumption (including poultry and deli meat), to reduce the carbon impact of diet (CI-d) without worsening other environmental impacts, while satisfying a set of nutrient intake recommendations (nutritional adequacy). Based on the average consumption of adults from the INCA3 survey, 10 diets were modeled under different assumptions. The results show that it is possible to achieve nutritional adequacy with 2 times less meat than today (62g/d vs. 124g/d), without supplements or fortified foods, while significantly reducing CI-d (by up to 50%). The modeled diet that was the closest to current consumption, which had CI-d reduced by 35%, contained meat (excluding deli meat), fish or eggs around 1 time per day, 3 dairy products per day, an abundance of minimally processed and unrefined plant-based foods (70% of solid weight, including 65g/d of pulses and 30g/d of nuts), 2.5 times fewer fatty, sweet and/or salty products. Such a diet, that conciliates nutritional and environmental targets, would also cost less (10% cost reduction).