From evidence to policy: Assessing causal claims in nutrition science

The aim of this chapter is to provide an overview of some of the main challenges that arise when claims about the relationship between food and (ill)health are assessed for the purpose of issuing health policies. As a case that helps to illustrate this topic, I discuss the controversy surrounding the health effects of meat eating: some researchers argue that the recommendations to reduce meat consumption are not trustworthy because they are based on evidence from observational studies. I show how standards of evidence that originate from the context of evidence-based medicine influence these discussions and argue that the application of the standards is problematic. Finally, I argue that even if high-quality evidence was available, it is not clear what nutritional policies should be issued.