The JPI HDHL launched its first joint action: DEDIPAC - the Knowledge Hub on the DEterminants of DIet and Physical Activity on November 2012. In the framework of DEDIPAC, a network of 56 research groups including 160 scientists from 12 JPI Member States have been selected to carry out a programme of joint trans- and multidisciplinary activities for a better understanding of how individual, social and environmental determinants influence food and physical activity choices. In order to make DEDIPAC become a success and initiate a sustainable and long- lasting international collaboration a 3-step process to establish and implement DEDIPAC has been set up including: the submission of a letter of Expression of Interest; which was the basis for a national selection process to nominate the hub members reflecting a great variety of disciplines (nutritional, food, health, behavioural and social sciences, psychology, epidemiology, etc.). a scientific networking and communication meeting which represented the starting point of a truly bottom up approach from scientists to funders to develop a joint transnational interdisciplinary DEDIPAC work programme proposal on how they would have realize activities for the benefit of the JPI HDHL. the presentation of a programme proposal which has been structured in three thematic areas (A: Data Assessment and Harmonization; B: Analysis of Determinants; C: Interventions and Policies) and coordinated by Johannes Brug (NL) with Paul Finglas (UK) and Ute Noethlings (DE) as deputy. The programme proposal has been peer reviewed by an international panel of expert and endorsed for funding by the end of September 2013. The DEDIPAC programme of activities officially started on December 1, 2013.