This empirical article presents the results of two interventions at different stages in the purchase process designed to influence consumer purchase behavior towards lower carbon products. Survey and questionnaire results show the potential for targeted interventions to increase awareness and understanding of complex sustainability initiatives, such as carbon labelling. Analysis of supermarket loyalty card data provides further evidence of the widely cited attitude-intention-behavior gap. The value of measuring the behavioral impact of interventions objectively is therefore highlighted. The challenge of attempting to change behavior within real world contexts, such as a retail supermarket setting, is illustrated and the consequences of this discussed. Our findings present valuable insights for researchers studying behavioral change and stakeholders attempting to influence pro-environmental purchasing behavior.