Am J Clin Nutr. 1999 Sep; 70(3 Suppl): 608S-614S.

Complex systems model of dietary choice with implications for improving diets and promoting vegetarianism.

Phillips CV.

Division of Environmental and Occupational Health, University of Minnesota School of Public Health, Minneapolis 55455, USA. carlp@cccs.umn.edu

An important step toward improving nutrition and promoting vegetarianism in the general population is to understand how consumers make dietary choices. Researchers from many clinical and social sciences are interested in dietary choice but have not combined their research into a comprehensive model to explain consumer actions. No one model has offered a good explanation for the fact that, although many people successfully change their diet significantly (often toward health-improving, plant-based diets) and are happy with the change, the public and health professionals often perceive dietary change as being difficult and unlikely to succeed. I have termed these observations "the paradox of dietary change." The present computer model uses the emerging science of complex systems analysis, which offers an intuitive method for studying evidence about dietary choice from many fields, including public health, clinical science, economics, sociology, marketing, and genetics, and for combining individual choice with social interaction. The results suggest an explanation for the paradox and methods for helping society shift toward healthier and more plant-based diets. In particular, they suggest how and why major changes might be easier to make than incremental ones, and why this makes dietary change seem more difficult to consumers than it actually is.