Maintenance of Weight Loss After Initiation of Nutrition Training

Interventions targeting dietary change, physical activity, and behavioral strategies yield clinically significant weight loss of at least 5% (1, 2). After this weight loss, most people tend to regain 1 to 2 kg per year, with faster rates of regain in the earlier years (3). To reduce weight regain, various strategies have been evaluated, including sequential dieting, meal replacements, medications, and behavioral approaches (4). Behavioral approaches help people learn and habitualize behaviors for navigating situations that might lead to lapses and relapse (5). One behavioral approach is teaching patients maintenance-specific skills thought to differ from initiation-specific skills (68). Some trials evaluating maintenance skills did not have a specific weight loss requirement, so maintenance-specific skills could not be fully tested (913). One notable exception is the WLM (Weight Loss Maintenance) trial, in which participants who lost at least 4 kg were randomly assigned to an Internet, a personal contact, or a self-directed maintenance intervention (14). Although the personal contact group had modestly less regain at 30 months than the other 2 groups, the intervention was resource intensive, involving monthly telephone calls and in-person visits every 4 months. Efficacious maintenance interventions are needed to help participants adopt maintenance-specific skills while being delivered in a resource-conserving way. We evaluated the efficacy of a maintenance intervention compared with usual care among patients who lost at least 4 kg in a weight loss program. Our innovative maintenance intervention focused on cognitive and behavioral processes involved in weight loss maintenance and was designed to conserve resources by being delivered primarily by telephone with decreasing frequency of contact. Methods Design Overview The design was a 2-group, parallel, randomized, controlled trial. Patients who lost at least 4 kg during a 16-week weight loss program were randomly assigned 1:1 to the maintenance or usual care group. The primary hypothesis was the group difference in mean weight regain at week 56; all follow-up weight measurements were assessed by blinded personnel. The first patient gave informed consent on 20 August 2012; the last date of follow-up was 18 December 2015. The study protocol was approved by the institutional review boards of Durham Veterans Affairs (VA) Medical Center and Duke University Medical Center before data collection. Although body composition was specified in the protocol, these specific data from the bioelectric impedance scales were not entered into our database. Setting Participants were recruited from 3 primary care clinics at the VA Medical Center in Durham and Raleigh, North Carolina. Group sessions were held at the Duke Center for Living and comprised patients from the 3 VA clinics. Eligibility Screening and Participants The study was conducted in 6 cohorts, each recruited over 6 to 8 weeks. Eligibility for the weight loss initiation program was determined in a 3-step process involving an electronic medical record data pull, a screening telephone call, and an in-person screening visit. Details of screening procedures were reported and are available in the protocol (Supplement 1) (15). In brief, patients identified via the data pull were mailed a recruitment letter. Patients called study staff in response to the recruitment letters or flyers posted at the VA clinics, or study staff called patients referred by providers through a consult in the electronic medical record. Patients who passed the telephone screen were scheduled for an in-person visit to determine their final eligibility, and eligible patients provided written informed consent. To be included in the study, patients had to be aged 18 to 75 years, have a body mass index (BMI) of 30 kg/m2 or greater, have a primary care provider, agree to attend visits, and have access to a telephone and reliable transportation. Exclusion criteria included liver disease; type 1 diabetes; most recent hemoglobin A1c in past 6 months 12% or greater; average systolic blood pressure over the past year and most recent blood pressure 160 mm Hg or greater; history of weight loss surgery; dementia, severe psychiatric illness, or substance abuse; weight loss of 10 lb or more in the previous 3 months; current enrollment in a lifestyle program; current weight loss medication; pregnancy or plans to become pregnant in the next 6 months; breastfeeding; lack of birth control if premenopausal; organ transplant recipient; heart issues in the past 3 months; cancer not in remission; pacemaker or defibrillator (because of the use of a bioelectronic impedance scale); emotional problems that would impede intervention adherence or interacting in a group environment; and inability to stand for measurements. Eligible patients were offered up to 6 group meeting times and chose one that they would attend every 2 weeks for 16 weeks (8 sessions total). Supplement. Study Protocol and Technical Appendix: Methods and SAS Code The weight loss program was an abbreviated version of a previous protocol that focused on calorie and fat restriction (16). It included education and strategies for behavior initiation as outlined in our theoretical model, including goal setting and self-monitoring of dietary intake and physical activity. Weight loss of 4 kg or more during this program was the final eligibility criterion for randomization; thus, recording of weight within 1 week of the first scheduled group visit (week 16) and at the end of the weight loss initiation intervention (week 0) was required for patients to be considered for random assignment. A uniform 4-kg criterion was used because it is clinically significant for the average participant (17) and was used in a previous weight loss maintenance trial (14). Randomization and Interventions Patients were randomly assigned 1:1 to maintenance intervention or usual care within initial weight loss strata (<10 kg vs. 10 kg) in block sizes of 4. The randomization scheme was generated via a uniform random-number generator and loaded into a tracking database. It could be accessed only by the study statistician or information technology personnel. Either the study's registered dietitian or the project coordinator randomly assigned the participants by using the tracking database, and participants were given their assignment by telephone within 1 week after their week-0 visit. Intervention participants were asked to return at week 2 for the first maintenance group session, whereas usual care participants were scheduled for the follow-up visit at week 14. The first participant was randomly assigned on 31 January 2013. The maintenance intervention involved transitions from initiation to maintenance skills and from group visits to individual telephone calls, as well as decreased frequency of contact (18). The intervention period was 42 weeks, followed by 14 weeks of no contact. Group visits occurred at weeks 2, 6, and 10. Individual telephone calls were made at weeks 4, 8, 12, 16, 20, 24, 32, and 40. Group sessions addressed maintenance caloric intake, weight self-monitoring, increasing and maintaining physical activity, obtaining social support from friends and family, and relapse prevention. All calls had a uniform structure that focused on 4 maintenance constructs outlined in our theoretical model and were deemed acceptable in a pilot test: satisfaction with outcomes, relapse-prevention planning, self-monitoring, and social support (19). To make salient satisfaction with outcomes, participants reviewed before and after photographs and were asked to discuss outcomes of weight loss that continued to motivate them. They then identified high-risk situations in which relapse might occur and developed a plan to navigate those situations. Next, they specified a frequency of self-weighing and used a 1.36-kg (3-lb) regain relapse threshold. If relapse occurred, the registered dietitian guided the patient to reinitiate and self-monitor his or her diet or physical activity. Finally, participants identified a primary support person and supportive behaviors and were encouraged to share their plans with their support person. The group sessions and telephone calls were delivered by 1 of 2 registered dieticians. Training included a review of theoretical principles and calls with mock participants, with feedback from the investigators. A co-investigator attended each group session and used a fidelity checklist to ensure that all protocoled elements were addressed. All maintenance telephone calls were recorded. Each week, the principal investigator, at least 1 co-investigator, and the registered dietitians met for 1 hour to review randomly selected intervention calls, and the investigators completed fidelity checklists and provided feedback. Usual care was chosen as the comparator to mimic the typical patient experience of no further intervention after participating in a weight loss program. The VA's MOVE! clinical weight loss program (20) was not used as a comparator because it focuses on weight loss. MOVE! and referral to a nutritionist were available as part of usual care. Participants in the intervention group were asked not to enroll in MOVE! or other lifestyle programs or to consult a nutritionist during the intervention, whereas usual care participants were told they could do both. In a post hoc chart review, we determined that 2 participants randomly assigned to usual care and 3 to the intervention group attended a MOVE! orientation visit but had no further involvement in the program during the 56-week maintenance phase. Outcomes and Follow-up All participants were scheduled for assessment appointments at weeks 0, 14, 26, 42, and 56 (weight loss initiation occurred at week 16 to week 0). All measurements were conducted by a research associate blinded to group assignment. Participants received $20 for the first 4 visits and $40 for the assessment