The aim of this paper is to highlight the importance of an evidence-based approach to the development, implementation and evaluation of policies aimed at improving nutrition-related health in the population. Public Health Nutrition was established to realise a population-level approach to the prevention of the major nutrition-related health problems world-wide. The scope is broad and integrates activity from local, national, regional and international levels. The aim is to inform and develop coherent and effective policies that address the key rate-limiting steps critical to improving nutrition-related public health. This paper sets out the rationale for an evidence-based approach to Public Health Nutrition developed under the umbrella of the European Network for Public Health Nutrition.