Lessons learned from digital dietary interventions targeting the preconception population

Within Public Health Nutrition, the preconception phase, has emerged as a particularly important window for promoting a healthy diet, as it affects both current and future health as well as health in the next generation. Different approaches are used to support dietary change in this phase, and digital interventions are viewed as particularly promising. In this review, we describe digital interventions addressing preconception diet, discuss challenges in targeting the preconception population and highlight issues related to digital designs and measuring intervention effects. We draw upon six digital interventions with dietary outcomes, in different target populations. Only two of the interventions were found to be effective in improving relevant aspects of the participants' diet, and these targeted specific and narrow groups or a single dietary component. Most of the intervention studies faced considerable challenges with recruitment. High attrition further complicated evaluation. In addition, there were difficulties related to participant engagement with the digital interventions. Challenges with lack of engagement, recruitment and attrition are not new insights within public health research, and we need to acknowledge the need for new approaches to recruitment, intervention development and evaluation. Alternative approaches such as citizen science and participatory action research in which the researchers work closely with the target population and other stakeholders during the whole process, should be explored. Moreover, as the current behavioural interventions that rely heavily on individual agency seem largely unsuccessful, future interventions should consider targeting more upstream and structural determinants of diet, rather than individual behaviour alone.