Journal of Clinical Epidemiology 56 (2003) 421–432 Physical activity and nutrition programs for couples: A randomized controlled trial Valerie Burke a,b, *, Nella Giangiulio a,b , Helen F. Gillam a,b , Lawrie J. Beilin a,b , Stephen Houghton c a University Department of Medicine, Royal Perth Hospital and Heartsearch, 50 Murray Street, Perth 6000, Australia b West Australian Institute for Medical Research, 50 Murray Street, Perth 6000, Australia c Centre for Attention and Related Disorders, Graduate School of Education, University of Western Australia, Stirling Highway, Nedlands 6009, Australia Received 12 September 2001; received in revised form 2 August 2002; accepted 3 December 2002 Abstract Diet and physical activity habits may deteriorate after cohabitation, leading to weight gain and increased risk of lifestyle diseases. We carried out a 4-month, randomized controlled trial of a diet and physical activity program for couples with a 1-year follow-up, comparing two methods of delivery. The program used six modules, which, after an initial group session, were mailed to the low-level intervention group. In the high-level intervention group, half of the modules were mailed, and the others were delivered at interactive group sessions. A control group received no intervention. Postintervention and at follow-up, physical fitness improved in the high-level group, saturated fat intake decreased in both intervention groups, and low-density lipoprotein cholesterol fell in the high-level group. Fewer participants in the high-level group became overweight or obese. Health promotion for couples can improve health behaviors and potentially lower the risk of lifestyle diseases in participants and their future families.  2003 Elsevier Inc. All rights reserved. Keywords: Health promotion; Marriage; Behavior change; Nutrition; Physical activity 1. Introduction In changing from a single lifestyle to cohabitation, cou- ples often adopt adverse health-related behaviors with de- creased physical activity and unfavorable eating patterns leading to weight gain [1–5] and increased risk of lifestyle diseases. There is a widespread perception that weight gain is associated with becoming married [6], and longitudinal data over periods up to 10 years show that weight gain follows marriage in men and women [1–3,7]. Couples beginning to cohabit have not been targeted specifically in health promotion programs. However, the role transition occurring at this stage of life [8] may be associated with the willingness to adapt behaviors and therefore may provide an opportunity to encourage positive health choices. For example, life-course influences food choice [9], and the change in role associated with marriage modifies fruit and vegetable consumption [10]. We carried out a pilot study to assess the acceptability and effectiveness of a 4-month * Corresponding author. University Department of Medicine, Royal Perth Hospital, Box X2213 GPO, Perth 6847, Australia. Tel.: 618-9224- 0276; fax: 618-9224-0246. E-mail address: vburke@cyllene.uwa.edu.au (V. Burke). 0895-4356/03/$ – see front matter  2003 Elsevier Inc. All rights reserved. doi: 10.1016/S0895-4356(02)00610-8 program, designed for couples, that attempted to encourage the adoption or maintenance of physical activity and a healthy diet [11]. The program built on the participants’ readiness to change health behaviors at this stage of the life- course and the support provided by involving both partners. Participants found the program valuable and achieved im- provements in self-efficacy for diet and physical activity, a decrease in the perceived barriers related to these behaviors, a decrease in fat consumption, increased intake of fruits and vegetables, and increased physical activity. The changes in diet and physical activity were accompanied by a significant decrease in blood cholesterol [11]. This pilot study did not provide long-term follow-up, so we carried out a further randomized controlled trial that included a larger number of couples and incorporated assessment at the end of the pro- gram and 1 year after beginning the program. The cost of such programs is critical to their dissemination, and for that reason we compared delivering the program using interactive group sessions versus the less expensive option of providing a program entirely by mail. 2. Participants and methods Couples were recruited by advertisement in the press and through publicity on radio and television programs and did