The influence of persuasive messages on healthy eating habits: a test of the Theory of Reasoned Action when attitudes and subjective norm are targeted for change

Abstract

Messages designed to improve healthy eating habits are all around us, often aiming to change our attitudes and perceptions toward specific eating behaviors so that we will adopt better habits. This study provides a test of the Theory of Reasoned Action (TRA) to better understand the impact of influence messages on healthy eating. This longitudinal cohort study examined the TRA within two systems of change: (1) when attitudes and (2) subjective norms were influenced by messages to increase fruit/vegetable consumption and prevent meal skipping. Participants were assigned randomly to one of three messages: (1) no-message control group, (2) attitude message, and (3) subjective norm message. For fruit/vegetable consumption, when attitude or subjective norm changed, TRA's predictions were not consistent with the data. With no change present, TRA's predictions were consistent with control group data. These results were not replicated with skipping meals. The only model to predict accurately participants' skipped meals was a simple causal string (attitudes impacted intentions which predicted behavior). Persuasive messages can influence healthy eating behavior, but the mechanism is not consistent with TRA predictions. Also, using messages to influence healthy eating subjective norms proved difficult.