Purpose: The aim of this study was to identify barriers to healthy eating among older people and children/adolescents. Method: Four focus groups; two with older people and two with children/adolescents were conducted in Denmark. The focus groups were moderated to discuss the experienced or potential behavioural change in terms of healthier eating, discussing pre-selected healthy and unhealthy food categories. The revised Social Cognitive Theory was used as a theoretical framework. Results: The study suggests that the main obstacles to change can be grouped into motivational and implementation barriers. The motivational barriers are unwillingness to change eating habits, satisfaction with current diets and misconception about their healthiness; relatively low health consciousness and unwillingness to become excessively health-oriented. Implementation barriers include remembering the change, absence of observable direct immediate results, social impact (for older people - the impact of family members and social image; for children and adolescents - the influence of parents and peers). For children and adolescents, availability and temptation of unhealthy foods and unavailability of good and palatable healthy foods appeared to be significant implementation barriers. Older people tended to emphasize that their eating habits, craving for unhealthy food and practical issues hindered healthy eating. In general, in the absence of health problems (and, in some cases, in the presence of illnesses), "liking" remains the main food choice criterion, including the healthy foods. Conclusion: The study presented a number of barriers to healthy eating identified by older people and children/adolescents. Based on the results of the study, further investigations should be undertaken in this area and practical implications can be suggested to break down the barriers to healthy eating.