Diet, genes, and obesity.

Competing Interests: Competing interests: We have read and understood the BMJ policy on declaration of interests and declare the following: AD is a fulltime staff member for the World Health Organization; this article was written in his personal capacity, and its contents do not reflect the policies or views of any third party. LJE has a part time secondment to Public Health England but wrote this editorial in her role as Reader in public health and obesity at Teesside University.