Weight Loss Patterns and Outcomes Over 12 Months on a Commercial Weight Management Program (CSIRO Total Wellbeing Diet Online): Large-Community Cohort Evaluation Study.

backgroundA greater understanding of the effectiveness of digital self-management programs and their ability to support longer-term weight loss is needed.

objectiveThis study aimed to explore the total weight loss and patterns of weight loss of CSIRO (Commonwealth Scientific and Industrial Research Organisation) Total Wellbeing Diet Online members during their first 12 months of membership and examine the patterns of platform use associated with greater weight loss.

methodsParticipants were Australian adults who joined the program between October 2014 and June 2022 and were classified as longer-term members, meaning they completed at least 12 weeks of the program, had baseline and 12-week weight data, and had a paid membership of ≥1 year (N=24,035). Weight loss and percentage of starting body weight loss were calculated at 3, 6, 9, and 12 months using 3 statistical approaches: (1) multiple imputations method, (2) all available data, and (3) complete data only. Among members with complete data (6602/24,035, 27.5%), patterns of weight loss and gain were examined, and how this related to total weight loss was explored.

resultsMembers were mostly female (19,972/24,035, 83.09%), aged 31 to 50 years (9986/24,035, 41.5%) or 51 to 70 years (12,033/24,035, 50.06%), and most members were classified as overweight or obese (23,050/24,035, 95.9%). Using multiple imputations, the average estimated weight loss was 5.9 (SE 0.0245) kg at 12 weeks, 6.7 (SE 0.0348) kg at 6 months, 6.2 (SE 0.0400) kg at 9 months, and 5.5 (SE 0.0421) kg at 12 months. At 12 months, more than half the members (12,573/24,035, 52.3%) were at least 5% below their starting body weight and 1 in 4 (5865/24,035, 24.4%) were at least 10% below their starting body weight. In the subsample with complete data, the average weight loss at 12 months was 7.8 kg. The most common (961/6602, 14.56% members) weight loss pattern over the first 12 months was 6 months of weight loss, followed by 6 months of weight maintenance. This group had an average weight loss of 10.6 kg at 12 months (11.9% of their starting body weight). In a subgroup of participants who consistently lost weight over the 12-month period (284/6602, 4.3% of the sample), weight loss reached up to 22.3 kg (21.7% of their starting body weight). Weekly platform use was positively associated with total weight loss (r=0.287; P<.001). Members who used the platform >30 times per week (approximately >4 times/d) were more likely to lose weight in the first 6 months of the program.

conclusionsThis commercial weight loss program was shown to be effective, with 1 in 2 members achieving clinically significant results after 1 year. Greater engagement with the platform was associated with consecutive periods of weight loss and greater weight loss success overall.