Just eating healthier is not enough: studying the environmental impact of different diet scenarios for Dutch women (31-50 years old) by linear programming

Eating healthier or vegetarian and vegan diets are suggested options to reduce the environmental impact of the current diet. In this paper, we demonstrate a method that is able to identify diets with reduced environmental impact and are more similar to the current diet than predetermined scenarios. All diets were adequate and consisted of commonly available foods. We used linear programming to find solutions that are as close as possible to the current diet of an average woman with age 31-50, first without any food groups' constraints and later by imposing constraints on meat, fish, dairy, and eggs. Finally, we use a similar technique to search for the closest diet that achieves the same environmental reduction as the most restricted option (no meat, fish, dairy, or eggs), without restrictions on products. In the optimization algorithm, we incorporate popularity of food products in order to design menus which are feasible for the Dutch population. The results show that simply eating according to guidelines does not guarantee a diet with an improved environmental profile. Removing meat and fish from the diet reduces the environmental impact by about 21 %. A healthy vegan diet reaches 30 % environmental impact reduction, but leads to a diet with many changes in comparison to a typical Dutch diet and without meeting one of the health constraints (EPA + DHA-Eicosapentaenoic acid + Docosahexaenoic acid). We show that it is possible to find less restrictive solutions than vegetarian or vegan diets that still satisfy all nutritional requirements and have less environmental impact than the current one. Just eating healthier is not enough in order to reduce environmental impact. However, designing a diet that meets dietary requirements must be a prerequisite for sustainable diets. Simply removing products from a diet can have as consequence that other products have to be added to compensate for the nutritional imbalances. We show, by using linear programming, that it is possible to reach 30 % reduction in the environmental impact with a diet which is relatively similar to the current one and could be more likely to be accepted.