Effect of participant motivation on rapid dietary changes in an intervention trial

Background Dietary intervention research with free‐living subjects relies on the ability of study participants to meet their dietary goals within the study timeframe. Little is known about underlying factors affecting compliance. Method Here, we examined whether motivation to enrol in a trial of low‐fat and/or energy‐reduced diets influenced the ability of healthy women to reach their dietary goals quickly. Results Of the women who had energy‐reduction goals (n=43), the 18 with an altruistic reason for participation had a much higher energy reduction success rate at 4 weeks (83%) than the 25 who gave self‐rewarding reasons (48%). Conclusions Education, body weight, family history of cancer and previous diet experience did not appreciably affect dietary outcomes. This observation suggests that the societal importance of the research should be stressed in strategies that seek to affect rapid reduction of energy intake in clinical trials.