Front-of-package (FOP) labels, highlighting key nutrition information of food products, have garnered interest as a means to promote healthy eating. However, previous studies have shown limited effects of FOP labels, warranting further investigation. This paper examines how an interpretive summary indicator FOP label influences consumers' cognitive, senso-emotional, and behavioural responses to (un)healthy ready-to-eat meals. Additionally, it explores the role of consumer motivations (health, pleasure, and sustainability) in relation to a FOP label. Two between-subject studies were conducted online (Study 1: N = 516) and in a lab (Study 2: N = 116), along with a real-life experiment in a lunch buffet (Study 3: N = 1166). Studies 1 and 2 revealed that consumer motivations had a greater impact than a FOP label on cognitive (nutrient content and healthiness perceptions, purchase intention) and senso-emotional (taste perceptions and emotions) responses. Motivations also moderated the FOP label's impact: FOP label improved emotions related to the unhealthy product among health-conscious consumers, suggesting a health halo effect. FOP label might also be a sign to consume more among those not motivated by health, pleasure, or sustainability. In Study 3, demonstrating the behavioural impact, FOP label either increased or had no effect on the proportion of healthy food consumed, depending on the product. The results indicate that FOP labels have limited and mixed effects on product responses and may even be counterproductive in promoting healthy diets among some consumers. These findings assist policymakers and food marketers in identifying consumer groups and products that benefit from FOP labels indicating better nutritional quality.