Promoting adherence to dietary guidelines for cancer prevention: protocol for a randomized controlled trial

The World Cancer Research Fund and American Institute for Cancer Research (WCRF/AICR) recommend that adults eat a diet rich in whole grains, vegetables, and fruit; limit consumption of "fast foods" and processed foods high in fat, starches, or sugars; and limit consumption of red and processed meat and sugar sweetened beverages (SSBs) to reduce cancer risk. The home food environment strongly influences dietary intake, yet few interventions target household-level changes to promote adherence to cancer-preventive guidelines. The current study evaluates the efficacy of a primary prevention intervention informed by the influence the home food environment on eating behavior. Index participants (n = 236) will be randomized to either nutrition education or to an experimental intervention that has a primary focus on optimizing availability of foods in the home to be consistent with WCRF/AICR guidelines. Adherence will be promoted through support from household members, accountability from coaches, and use of self-regulation strategies such as implementation intentions. The primary outcome is change in adherence to WCRF/AICR guidelines in the index participant. Secondary outcomes include change in dietary quality in adult household members (n = 236) and change in markers of inflammation in index participants. The findings will be relevant not only to the field of cancer prevention, but to the prevention of other diseases for which dietary quality is important. If effective, this household-focused approach could offer a scalable strategy for cancer prevention through improved dietary quality, with implications for public health policy and multi-disease prevention.