The paper describes the use of research in a specific field of social marketing. For the Federal Republic of Germany, government attempts to influence the population's nutrition behaviour are being analyzed. The empirical evidence is based on all available published or unpublished case studies 1980-88 which evaluate relevant political activities trying to motivate, inform, advise or educate German consumers with respect to nutrition issues. Criteria for evaluation are activity benefits as expressed by its coverage among the population and by its behavioural effects among activity users, as well as activity costs. Problems in measurement are being discussed, both methodological and institutional ones. Activities are found to have been researched in a non-representative way. Research standards show serious limits to the validity and reliability of some of the results obtained. Many studies investigate the structure of activity coverage but neglect its behavioural effects and, even more often, its costs. Self-completion questionnaires dominate among the methods for data collection. Sampling plans and response rates often appear insufficient. It is suggested that the deficits express restrictions on type and volume of research resources and on available methods, and that they also reflect competing research targets. An overview of empirical results shows that activity success varies considerably and can with respect to behavioural effects, coverage and costs systematically be influenced by activity choice and design. Research thus contributes to judge, explain and improve policy success.