In recent years, concerns over the sustainability of food consumption patterns in high-income countries have emerged due to the now well-documented negative effects of some diets on both health and the environment. Research seeking improvements generally supports a move away from animal-based products towards plant-based products, but the role that fish and seafood might play in sustainable diets remains unclear. In particular, little is known about how promotion of fish consumption through generic advertising and other informational measures might affect the environmental and health properties of whole diets, nor whether that type of promotion would be cost-effective; that is, represent money well spent from a societal point of view.
This study adapts a model of whole-diet adjustment to dietary constraints to simulate how French and Finnish consumers would change their diets if urged to raise their consumption of fish at the margin (that is, by a small amount from currently observed levels). The behavioural model, which is based on a rationality assumption and preferences estimated from observations on actual food purchases, captures the relationships of substitutability and complementarity among foods, and produces a quantitative estimate of the difficulty for consumers to modify their diets in a given way (for instance by eating more fish). The whole-diet adjustments simulated by the behavioural model are then linked to an epidemiological model to estimate health effects and a life-cycle analysis model to estimate climate effects. Monetization of the health and environmental benefits then permits the development of a cost-effectiveness analysis of the dietary change. The sustainability effects of raising consumption of fish by an arbitrarily-chosen 5% is compared to that of decreasing consumption of all meat and meat from ruminants by 5%.