Extending Weight Loss Programmes Helps People Keep Weight Off and Is Cost-Effective, Study Finds

Weight management is a growing challenge for millions across the UK, with obesity driving up rates of diabetes, heart disease, and hypertension. The NHS has long relied on 12-week commercial weight loss programmes, such as those run by Weight Watchers, to help people shed excess weight. But how effective are these short interventions in the long run? A groundbreaking study published in The Lancet on 4 May 2017 provides a clear answer: extending weight loss support to a full year not only helps people keep weight off, but also improves health outcomes and proves highly cost-effective for the NHS.

The WRAP Trial: A Landmark Study

The Weight Loss Referrals for Adults in Primary Care (WRAP) trial, led by researchers from the Universities of Cambridge, Liverpool, and Oxford, set out to compare the effectiveness of different weight loss strategies for adults with a BMI of 28 or higher. The study involved 1,267 participants, who were randomly assigned to one of three groups: a self-help group that received a booklet of advice, a standard 12-week commercial weight loss programme, or an extended 52-week (year-long) programme.

Weight Loss Results: The Longer, the Better

After one year, the average weight loss was 3.3kg in the self-help group, 4.8kg in the 12-week group, and an impressive 6.8kg in the year-long group. Even after two years, when some weight had been regained, the year-long group remained 4.3kg lighter, compared to 3.0kg in the 12-week group and 2.3kg in the self-help group. This evidence shows that longer programmes not only help people lose more weight initially but also support better weight maintenance over time.

Health Benefits Beyond Weight Loss

The benefits of a year-long programme extend beyond the scales. Participants in the extended group saw greater improvements in key diabetes markers, such as fasting blood glucose and glycosylated haemoglobin (HbA1c). On average, blood glucose fell by 0.54 mmol/L in the year-long group, compared to 0.27 mmol/L in the 12-week group and 0.11 mmol/L in the self-help group. These improvements are clinically

significant, as they reduce the risk of developing type 2 diabetes and other metabolic conditions.

Cost-Effectiveness: A Smart Investment for the NHS

One of the most important questions for public health is whether longer programmes are worth the extra investment. The WRAP trial’s economic analysis modelled the impact of each approach over 25 years, using a measure called QALYs (quality-adjusted life years), which combines both length and quality of life.

The 12-week programme was cost-saving overall, preventing diseases and saving the NHS £268,000 per 100,000 people while adding 643 QALYs. The year-long programme, while not immediately cost-saving, prevented an additional 1,786 cases of chronic disease and was highly cost-effective, with a cost of £2,394 per QALY gained compared to self-help, and £3,804 per QALY compared to the 12-week group. Both figures are well below the NICE funding threshold of £20,000 per QALY.

Expert Commentary and Independent Analysis

Professor Susan Jebb of the University of Oxford, senior author of the study, highlighted the long-term value of extended support: “Our results show that offering longer-term support through weight loss groups not only helps people keep weight off but is cost-effective in the long run by preventing diseases like diabetes and heart disease.” Lead author Dr Amy Ahern from the MRC Epidemiology Unit at the University of Cambridge added: “This is the first time we’ve shown that extending a commercial programme to a full year leads to sustained weight loss and greater health benefits. These improvements are comparable to much more expensive, clinician-led interventions.”

In a linked commentary, Dr Emily Brindal of CSIRO supported the findings, stating: “Prolonged access to weight loss programmes appears to be a simple and scalable way to improve long-term outcomes. Initial weight loss plays a key role in long-term success.”

Limitations and Considerations

The study did note some limitations. Not all participants attended every session, with average attendance at 8 of 12 sessions in the standard programme and 28 of 52 in the year-long programme. Some in the self-help and 12-week groups also accessed weight loss support outside the study, which may have influenced results. Additionally, some costs may have been overestimated. Nevertheless, the overall trends are clear and robust.

Policy Implications: What Should the NHS Do Next?

The evidence strongly supports extending access to longer-term weight loss programmes, but Professor Jebb emphasised that the first priority should be ensuring everyone has access to at least the standard 12-week programme, which is already proven to be cost-saving and effective. For those who need additional support, offering year-long programmes could deliver even greater health and economic benefits.

Conclusion

The WRAP trial provides compelling evidence that extending weight loss programmes to a full year helps people lose more weight, keep it off, and enjoy better health outcomes, particularly in reducing the risk of chronic diseases like diabetes and heart disease. While longer programmes require more upfront investment, they are highly cost-effective for the NHS in the long term. As obesity rates continue to rise, these findings make a persuasive case for rethinking how the NHS supports people on their weight loss journeys—proving that sometimes, longer really is better.