Understanding successful behaviour change: the role of intentions, attitudes to the target and motivations and the example of diet.

Although many attempts to change health behaviour fail, some individuals do show successful behaviour change. This study assessed the role of behavioural intentions, motivations and attitudes to the target in explaining successful changes in diet with a particular focus on positive and negative intentions and positive and negative attitudes. Participants (n=282) completed a questionnaire describing a recent change in eating behaviour (becoming a vegetarian, cutting out a food group, eating fewer calories), their intentions, their attitudes to the food being avoided, a range of motivations and their degree of success. The results showed that the three behaviour change groups differed in terms of their cognitions with those trying to eat fewer calories reporting less success in changing their behaviour. Successful vegetarianism was associated with a lower positive attitude; successfully cutting out a food group was related to ethical motivations, a lower positive attitude and greater positive and negative intentions, and reducing calorie intake was associated with greater positive intentions and a lower positive attitude. Therefore, success was associated with different cognitions depending upon the type of change being made, although cognitions such as 'I will eat more vegetables' and 'I no longer find high fat foods palatable' were consistently most predictive of success. Suggestions for the development of more effective interventions to change health behaviours are made.