Objectives: The purpose of the present study was to assess the role of implicit attitudes towards food and automatic approach/avoidance tendencies in dietary restraint. Research suggests that positive implicit attitudes towards high-fat, calorie-dense food may contribute to impulsive eating behaviour when self-control capacity is diminished ('ego depletion') - as is the case with dietary restraint. We hypothesised that both dieters and non-dieters would hold positive implicit associations with high-fat food and that dieters would have stronger approach tendencies for high-fat food. We were also interested in an exploratory assessment of differences between successful and unsuccessful dieters. Design: We adopted a between-subject design to assess differences in implicit food attitudes and automatic approach/avoidance tendencies towards food in current dieters and current non-dieters, and between successful and unsuccessful dieters. Methods: One hundred and thirty eight female participants completed an implicit association test (TAT) as a measure of implicit attitudes towards high-fat (HF) and low-fat (LF) food, a series of questionnaires to assess their eating behaviours and explicit attitudes, and a pictorial reaction time task to assess approach and avoidance for HF and LF food. Findings: Explicitly, participants in all groups reported a preference for HF over LF food. Current non-dieters had a significantly stronger implicit preference for HF over LF food compared to current dieters, who did not have a preference for either. Successful dieters had a marginally significant preference for HF food: unsuccessful dieters did not have a significant preference for either. Data from the approach/avoidance task did not support the role of ego depletion in restrained eating. Conclusions: The results suggest that implicit preference for HF food may decrease as a consequence of dietary restraint, particularly in unsuccessful dieters. However, these differences were not reflected in self-report, which suggest some degree of implicit-explicit dissonance in unsuccessful restrained eaters. The hypothesis that positive implicit attitudes towards HF food may drive impulsive eating as a consequence of ego depletion was not supported. Further research is needed to clarify the causal links between restraint and the cognitive changes observed, and the dietary strategies associated with successful and unsuccessful restraint.
