Application of behavior change techniques in a personalized nutrition Electronic Health intervention study: protocol for the web-based Food4Me randomized controlled trial

Background: In order to determine the efficacy of behavior change techniques (BCT) applied in dietary and physical activity intervention studies, it is first necessary to record and describe techniques which have been used during such interventions. Published frameworks used in dietary and smoking cessation interventions undergo continuous development and most are not adapted for online delivery. The Food4Me study (N=1607) provided the opportunity to use existing frameworks to describe standardized online techniques employed in a large-scale internet-based intervention to change dietary behaviour and physical activity. Objectives: To describe techniques embedded in the Food4Me study design and explain the selection rationale. To demonstrate the use of behaviour change technique taxonomies, develop standard operating procedures for training, and identify strengths and limitations of the Food4Me framework that will inform its use in future studies. Methods: The 6-month randomized controlled trial took place simultaneously in 7 European countries, with participants receiving one of 4 levels of personalized advice (generalized, intake-based, intake+phenotype-based and intake+phenotype+gene-based). A 3-phase approach was taken: (I), existing taxonomies were reviewed and techniques were identified a priori for possible inclusion in the Food4Me study; (II) a standard operating procedure was developed to maintain consistency in the use of methods and techniques across research centers; (III) the Food4Me BCT framework was reviewed and updated post intervention. An analysis of excluded techniques was also conducted. Results: Of 46 techniques identified a priori as being applicable to Food4Me, 17 were embedded in the intervention design. Eleven were from a dietary taxonomy and 6 from a smoking cessation taxonomy. In addition, the 4-category smoking cessation framework structure was adopted for clarity of communication. Smoking cessation texts were adapted for dietary use where necessary. A posteriori, a further 9 techniques were included. Examination of excluded items highlighted the distinction between techniques considered appropriate for face-to-face vs internet-based delivery. Conclusions: The use of existing taxonomies facilitated the description and standardization of techniques used in Food4Me. We recommend that for complex studies of this nature, technique analysis should be conducted a priori to develop standardized procedures and training, and reviewed a posteriori to audit the techniques actually adopted. The present framework description makes a valuable contribution to future systematic reviews and meta-analyses which explore technique efficacy and underlying psychological constructs. This was a novel application of the behavior change taxonomies, and was the first internet-based personalized nutrition intervention to use such a framework remotely