Inappropriate diets constitute an important health risk and an increasing environmental burden. Healthy regional diets may contribute to meeting this dual challenge. A palatable, healthy and sustainable New Nordic diet (NND) based on organic products from the Nordic region has been developed. This study assesses whether a large-scale introduction of NND is a cost-effective health promotion strategy by combining an economic model for estimating the utility-maximizing composition of NND, a life cycle assessment model to assess environmental effects of the dietary change, and a health impact model to assess impacts on the disease burden. Consumer expenditure for food and beverages in the NND is about 16% higher than currently, with the largest relative difference in low-income households. Environmental loads from food consumption are 15%–25% lower, and more than 18,000 disability-adjusted life years (DALY) will be saved per year in Denmark. NND exhibits a cost-effectiveness ratio of about €73,000–94,000 per DALY saved. This cost-effectiveness improves considerably, if the NND’s emphasis on organic and Nordic-origin products is relaxed.