Improving compliance to meal-replacement food regimens. Forming implementation intentions (conscious IF-THEN plans) increases compliance.

Creating and changing habits around dieting behaviour can be a way to help consumers to consume more healthy products and to control their weight. Previous studies suggested that implementation intentions – deliberate plans on when, where and how – increase the likelihood that consumers perform the intended behaviour (Armitage, 2004; Gollwitzer and Sheeran, 2006 ;  Jackson et al., 2005). This study investigated the effect of forming implementation intentions on compliance to a regimen based on a range of meal-replacement food products and snacks. Participants (n = 57) were allocated to one of two groups, either: (1) an implementation-intention group, who formed deliberate plans (implementation intentions) to consume the products – these implementation intentions were formed only once at the beginning of the study –, or (2) a control group who formed no implementation intentions. Participants were then instructed to follow a daily regimen, which included the consumption of foods from a range of meal-replacement products and snacks provided gratis for four weeks. Results showed that the implementation-intention group consumed significantly more meal-replacement food products per week (p < 0.05) and decreased their BMI score more than did the control group (p < 0.05). The effect of forming the implementation intentions was apparent for 18 days. These findings indicate that forming implementation intentions may assist individuals in their compliance to a meal-replacement product regimen.