BACKGROUND: Eating in moderation, i.e. the attempt to monitor and limit the intake of energy-dense foods, is a promising strategy in the prevention of weight gain. The purpose of this study was to examine which psychosocial factors derived from the I-Change Model (ICM) were associated with eating in moderation, and whether these factors differed between adults with a correct (aware) or incorrect (unaware) perception of their dietary behaviour. METHODS: This study used a longitudinal design with measurements at baseline (N = 483) and six-month follow-up (N = 379). Eating in moderation was defined as the average daily energy intake from energy-dense food products and was measured by a validated food frequency questionnaire. Predictors included demographics and the ICM factors awareness, risk perception, attitude, social influence, self-efficacy and intention. Linear regression analyses were used to assess the associations between these factors and eating in moderation. The moderating role of awareness was examined by including interactions between awareness and the ICM factors in the regression analyses using the pick-a-point approach to further examine the associations for aware and unaware participants. RESULTS: Participants who were aware of their dietary behaviour (51.9%) had a significantly (t = -3.68, p < 0.01) lower average daily energy intake (mean = 835.1, SD = 404.1) compared to those who were unaware (mean = 983.4, SD = 367.9). Eating in moderation was predicted by demographic variables such as gender, age, educational level and body mass index, as well as awareness, risk perception, social influence and intention. Among the aware participants, eating in moderation was predicted by demographic variables and risk perception, attitude, social influence and intention. Among the unaware participants, besides several demographics, only risk perception and self-efficacy were significantly associated with eating in moderation. CONCLUSIONS: In line with prior research, our findings show that psychosocial ...