Funding for this research was provided by:
Wellcome Trust (106679/Z/14/Z, 206853/Z/17/Z)
Cancer Research UK (C4770/A29425)
Text and Data Mining valid from 2019-12-01
Received: 28 October 2019
Accepted: 8 November 2019
First Online: 2 December 2019
Ethics approval and consent to participate
: The Cambridge Psychology Research Ethics Committee based at the University of Cambridge approved the trial on 14th May 2019 (No. PRE.2019.006). The research team obtained written consent from a representative of the supermarket group on behalf of the participating sites.
: Not applicable
: The authors declare that they have no competing interests.