Though some form of weight loss is accessible to many, weight loss maintenance over the longer term using traditional public health interventions has proven elusive for many people living with obesity. We were interested to learn about research published recently in Lancet Public Health and discussed this with Dr Amy Ahern, MRC Epidemiology Unit, University of Cambridge
Please describe the WRAP study design.
WRAP is a randomised controlled trial to test the cost-effectiveness of a commercial weight management programme (WW, WeightWatchers®) for different durations. We recruited people living with overweight or obesity from primary care practices and randomly allocated them to one of three intervention groups. The first group received a brief intervention – a booklet of information on how to lose weight and keep it off. The second group received free access to the WW programme for 12 weeks. The third group received free access to WW for 52 weeks. We then followed participants up at 3 months, 1 year, 2 years, and 5 years to see what had happened to their weight and other outcomes. We then modelled the effect that these changes could have on health and health care costs over a lifetime.
Thanks a lot – please tell us about what you found.
Over the first two years of the trial, people randomised to the commercial weight management programme (WW) lost more weight than those in the brief intervention group. Those who received 52 weeks of WW lost more than those who received 12 weeks. After 5 years, all groups regained some of the weight that they had lost, but those in the WW groups still maintained some weight loss – about 2kg. When we modelled the effect that this would have on health and health care costs over the lifetime, both the 12-week and 52-week programme were cost-saving – that means the cost of the intervention was outweighed by reductions in health care costs over the lifetime. Although it costs more initially, the 52-week programme saved the most money because of greater reductions in diabetes, heart disease and other weight-related diseases.
The WRAP study is novel. Can you describe stand-out features of the research?
WRAP is the first randomised controlled trial of this type of weight management programme to collect outcome data at 5 years. This long term data is important, because the health impact of weight management interventions is dependent on what happens to participants’ weight after the intervention ends. We have previously assumed that on average, weight lost as part of a commercial weight loss programme is regained within 5 years. This study suggests that this is not true and that some weight loss is maintained up to 5 years.
What are the implications for weight management interventions of the trial and of simulations modelled beyond five years?
Referral to commercial weight loss programmes like WW is a cost effective way to support people with obesity to lose weight and improve their health. While this type of programme is not suitable for everyone, it is a scalable, relatively low cost option that should be made available to people living with obesity who want to lose weight.
The research is published here: https://www.thelancet.com/journals/lanpub/article/PIIS2468-2667(22)00226-2/fulltext