Young adults often experience deterioration in eating habits during transition periods. However, longitudinal evidence on the changes of eating styles and associated determinants remains limited. This study aimed to explore the eating style transitions among young adults in their graduate transitions and investigate the influences of top-down regulatory factors and bottom-up environmental cues on their eating style transitions. This is a two-wave cohort study involving 594 Hong Kong young adults completing the baseline assessment during their post-secondary graduation year, of whom, 424 completed the one-year follow-up survey. Eating behaviours were measured at both points. Executive function (EF), coping style, exposure to digital food environments, responsiveness to food cues, perceived stress and demographics were also measured. Latent profile analysis was used to explore main eating styles among participants while multinomial logistic regression models were used to assess determinants of eating style transitions. In follow-up assessment, 5.9 % of participants were consistently approaching eaters (APE) across two time points, while 28.8 % have transitioned from moderate eaters (MOE) or APE to mixed eaters (MIE). The multinominal logistic regression model revealed that although EF and coping style were no longer significantly associated with participants' eating style transitions outcomes, greater exposure to digital food environments (OR = 2.60, p = 0.028) and higher responsiveness to food cues (OR = 5.86, p = 0.005) were associated with Persistent APE, while higher responsiveness to food cues (OR = 2.36, p = 0.009) and higher perceived stress (OR = 1.05, p = 0.046) were associated with Converted MIE. Bottom-up cues may dominate eating style transitions compared to top-down regulations. Future interventions should leverage environmental cues, thereby targeting the automatic decision-making process and supporting healthy eating habits during stressful life stages.