The Health of the Nation report (Department of Health, 1992) set targets for population dietary intake which will necessitate widespread changes in eating behaviour. The recent Committee on Medical Aspects of Health Policy report (Department of Health, 1994) indicates how these targets might be achieved by providing examples of practical strategies that people could adopt. However, despite the abundance of official recommendations and sources of information about dietary issues, there appears to have been relatively little change in the intake of certain nutrients at the population level. If the recent recommendations are to be heeded, it is likely that an emphasis on a general need for changes (even when combined with an indication of what those changes should or could be) needs to be supplemented by more effective means of influencing dietary choices. Hand-in-hand with increasing and widespread acknowledgement of a link between diet and health, there has been both historical change in the direction of dietary advice (for a discussion of the evolution of dietary advice see Cannon, 1992) and some dispute between ‘experts’ about nutritional issues; it is often suggested that these have served to provoke some confusion in the public mind about dietary recommendations. To confound this problem, there has been a good deal of debate about where dietary advice efforts should be targeted; while some have suggested that strategies ought to be directed at the broader population level, others have voiced a preference for targeting ‘at risk’ individuals. This latter debate serves to raise a question mark for many people about the personal applicability of dietary advice. For whom is dietary advice relevant? A number of researchers and practitioners involved in health promotion and health psychology are paying increasing attention to the ‘unrealistic optimism’ phenomenon which has been widely discussed as having important practical implications for health. In the present short review paper, we present a brief general discussion of dietary intervention strategies, outline the ‘unrealistic optimism’ phenomenon, critically assess its implications for the promotion of dietary change and give a brief review of recent research which has been addressing the issues raised. For the purpose of brevity, we shall concentrate on the reduction of fat consumption as the main dietary theme that we address.