Does message framing affect intentions to improve diet and physical activity? A randomized study in UK adults

Engaging in regular physical activity and a healthy diet, in line with World Health Organisation (WHO) recommendations, have robust benefits on physical and mental health. One way to influence behaviour change is by improving the effectiveness of health communication. This study of 190 participants explored the effectiveness of message framing and temporal focus on behavioural intention to increase physical activity and improve diet. In this cross-sectional between-subjects design, ANCOVAs were conducted to investigate the main effects of message frame, message focus and the interaction effects on behavioural intentions with respect to diet and PA. Furthermore, regression analyses were used to determine the predictors of behavioural intentions (including perceived stress and BMI). Previous research suggests that BMI moderates responses to gain-framed messages, while stress impairs impulse control and affects dietary choice, making them critical variables in understanding behaviour change. Therefore, BMI and stress are included in the study because both factors could influence health behaviours and the effectiveness of message framing. There were no significant main effects or two-way interactions for the frame of focus on intentions to be more physically active. However, there was a significant three-way interaction between temporal focus, message frame and stress, such that people with higher perceived stress had a greater intention to improve their diet when the message was gain-farmed and had a focus on short-term rather than long-term gains. Furthermore, BMI was a significant predictor of both diet and intentions to be more physically active. The findings highlight the need for more research on the potential efficacy of message framing in health communication for preventive behaviours.