Globally more than 50% of adults are overweight or obese.¹ Ireland has one of the highest obesity rates in Europe. It affects more than one million people here; one in four adults are obese and one in four children are overweight or obese.² The current cost of treating obesity-related disease in Ireland is approximately €1.16 billion a year.³ The government is being called on to implement a national obesity treatment programme to reduce this financial and societal burden. Lifestyle programmes, targeting diet and exercise improvements, produce clinically-relevant weight changes and can be delivered on a large scale. Such lifestyle programmes are a popular approach to weight management despite better long-term weight loss outcomes seen using different methods, in particular bariatric surgery.

Ahern et al⁴ based in Cambridge, UK, assessed the effects of extended access to a group-based, commercial weight loss programme (Weight Watchers). They recruited 1,267 adults who were overweight or obese through primary care practices in England and randomly assigned them to one of three pathways: a brief intervention of nutritional advice based in the practice; a 12-week commercial programme; or a 52-week commercial programme.

Both groups referred to the commercial programme showed better weight loss outcomes than the brief intervention group. Mean weight loss in participants given a 52-week referral was 6·76kg at 12 months and 4·29kg at 24 months, which represented 2·14kg and 1·32kg greater weight loss compared with the 12-week referral group. Although modest, these differences are relevant to the objectives of the study, which aimed to understand whether extended access to a weight management programme could improve weight loss in a real-world setting. The findings also suggest that referral to commercial weight loss programmes might be cost effective in terms of expected reductions in morbidity and future use of health resources.

Weight reduction programmes that rely on behavioural change are dogged by the tendency to regain weight after the intervention ceases. So for successful weight maintenance, the length of access to treatment might need to extend to two to five years or indefinitely. So a shift is required away from the current thinking of separating active intervention and weight regain prevention towards weight management as a single, dynamic and ongoing process.

Extending the duration of weight-loss intervention leads to the need to consider whether participants continue to engage with the programme. Despite greater weight loss, only 29% of participants in the 52-week referral group reported regular attendance at group sessions in the 12 weeks preceding week 52. Thus close to three-quarters of participants appear to be failing to engage in the programme after 12-24 months. 

This study shows that weight reduction interventions are effective in achieving modest weight reduction but that behavioural change must be sustained, possibly through ongoing support. For more severe obesity, surgical therapies are probably more effective and the role of pharmacological treatments is unclear.

References

1. WHO. Fiscal policies for diet and prevention of non-communicable diseases. Technical Meeting Report (5–6 May 2015). Geneva: World Health Organization Document Production Services, 2016 
2. Report of the National Taskforce on Obesity: Obesity – the policy challenges, 2005. http://health.gov.ie/wp-content/uploads/2014/03/Obesity-the-policy-challenges.pdf
3. Dee A et al. Overweight and obesity on the island of Ireland: an estimation of costs. BMJ Open 5, e006189, doi:10.1136/bmjopen-2014-006189 (2015)
4. Ahern AL et al. Extended and standard duration weight loss referrals for adults in primary care (WRAP): a pragmatic randomised controlled trial. Lancet (2017) http://dx.doi.org/10.1016/S0140-6736(17)30647-5