Associations between stress, emotions and unhealthy eating have been reported, yet findings remain inconsistent. Stress eating and emotional eating have frequently been used interchangeably despite potential differences regarding physiological and psychological explanations. To aid in disentangling the shared and unique effects of stressors and emotions, we examined their associations with distinct aspects of eating behaviour (food craving, quantity, healthiness and snacking) in daily life in an experience-sampling study. Participants (N = 64) responded to six daily smartphone prompts over 4 weeks, reporting stressors, multidimensional emotional states (valence, arousal, calmness) and eating behaviour. Bayesian multilevel models revealed that general stressors were unrelated to snacking (OR = 1.07, 90% CI = [0.87, 1.32]), but episodes of time pressure increased snacking likelihood (OR = 1.34, 90% CI = [1.01, 1.75]) while being associated with lower food quantity (B = -2.45, 90% CI = [-4.07, -0.82]). Arousal was associated with more food intake (B = 0.04, 90% CI = [0.001, 0.087]), while there was no other emotional state-eating association. Together, these results indicate that changes in snacking behaviour are more strongly linked to specific situational constraints, such as time pressure, than to momentary emotional fluctuations. Emotional eating, operationalised as emotion-driven snacking independent of stressors, received little support in this sample. These findings suggest that interventions may benefit from targeting situational constraints, such as time pressure.