Individual preferences for diet and exercise programmes: changes over a lifestyle intervention and their link with outcomes.

Objective: To investigate the influence of a trial lifestyle intervention on participants' preferences for a range of exercise and diet programmes and whether these differ between successful and unsuccessful participants.

Design: Hypothetical scenarios that describe attributes of diet and exercise programmes were developed using an experimental design. Participants completed an online questionnaire at baseline, 16 weeks and 12 months where they chose their most preferred of three programmes in each of sixteen scenarios. Discrete choice modelling was used to identify which attributes participants emphasised at each time point.

Subjects: Fifty-five individuals who exhibited symptoms of metabolic syndrome and who participated in a 16-week trial lifestyle intervention.

Results: There was a clear shift in programme preferences from structure to flexibility over the intervention. At baseline, emphasis was on individually designed and supervised exercise, structured diets and high levels of support, with Gainers focusing almost exclusively on support and supervision. Losers tended to consider a wider range of programme attributes. After 16 weeks preferences shifted towards self-directed rather than organised/supervised exercise and support was less important (this depended on the type of participant and whether they were in the follow-up group). Cost became significant for Gainers following the end of the primary intervention.

Conclusions: The stated preference method could be a useful tool in identifying potential for success and specific needs. Gainers' relinquishment of responsibility for lifestyle change to programme staff may be a factor in their failure and in their greater cost sensitivity, since they focus on external rather than internal resources.