Fifty shades of grain - Increasing whole grain consumption through daily messages

Despite numerous health benefits, the majority of consumers, in particular young adults, show low levels of whole grain consumption behaviour (WGCB). In order to increase WGCB, this pre-registered experimental study investigates the effect of a two weeks message intervention. Participants (n = 329) received either information about health benefits, recipe suggestions, a combination of both, or about a control topic. We evaluated WGCB at three time points: prior to, immediately after (post), and one month after the intervention (follow-up). Our findings show that participants read the message on most of the days and on average, evaluate the health-only message most positively. Furthermore, we found that health messages, but not recipe suggestions significantly increase WGCB at the follow-up measure. This effect was serially mediated by attitudes and behavioural intentions at the post-intervention measure, with more positive attitudes and higher intentions leading to more WGCB. Although health messages are an effective tool to influence WGCB, the effect is small in magnitude and consumption levels remain rather low. We discuss implications for future research and for the communication of whole grain related health benefits among different stakeholders in the health sector.