September 27, 2018

expert reaction to study looking at total diet replacement programmes and obesity

Researchers, publishing in the BMJ, report that a total diet replacement programme offered through GP referrals was effective in treating obesity.

Dr Scott Harding, Visiting Senior Lecturer in Nutritional Sciences, King’s College London, said:

“The study published today in BMJ by Astbury and colleagues addresses a significant knowledge gap for primary healthcare practitioners, specifically, what is the best way to help obese individuals achieve meaningful weight loss and keep the weight off for the long-term.  The results of this study show that there is a role for commercial weight loss companies in a treatment plan for people presenting as obese to their primary healthcare team.

“Some key next steps to solidifying the case for potentially covering to costs of such commercial weight loss programs are 1) identifying the essential parts of the weight loss support program that are critical to achieving and maintaining the weight loss and 2) conducting a secondary analysis of this data from a health care economics perspective.  Ideally, a true economic comparison between the costs to the NHS – over say the next 5 years – to treat these individuals if they did not reduce their body weights versus the cost of providing them with the commercial weight loss program.

“An additional hurdle for the adoption of a primary health care policy that covers the cost of a commercial weight loss program is the fact that the weight loss industry is not regarded in the same class as other commercial industries that are partners in providing healthcare.  The pharmaceutical, medical devices and clinical nutrition industries are all regarded as partners in healthcare provision with no hesitation by the NHS (or public health care providers in other countries) to cover the cost of the products from these industries.  However, the weight loss industry is not held in the same regard and unfortunately those with clear evidence-based programs and excellent track records of success can be lumped in with less credible or ‘snake-oil’-type companies selling quick fixes with not a shred of scientific evidence supporting their usefulness.  While the results of this study clearly indicate the success in weight loss that can be achieved through a commercial weight loss program (e.g. using total diet replacement and personal support), wide spread adoption of the approach by primary care teams still has a number of hurdles to overcome.

“Regarding the study design itself, the nature of this comparison does not allow for blinding of the treatments but the independent oversight by a trial steering committee, independent statistical analysis and clear focus on reporting the results of the primary outcomes are key strengths of this trial.  The major weakness is that both treatments (i.e. standard care and TDR) have multiple aspects that could drive the outcomes observed.  Therefore, there are both positive and negative aspects of each approach that could be contributing to the weight loss or lack of weight loss.  As a result, the successful weight loss observed is in the context of primary care directed weight loss but this study will undoubtedly also be interpreted in the context of self-directed weight loss which might yield very different results.

“Overall, this study is well-designed with a robust sample size and the data presented are of a high quality and supportive of the main conclusions of the paper.”

Dr Katarina Kos, senior Lecturer in diabetes and obesity, University of Exeter Medical School, said:

“The strength of the study is that it retained nearly everyone for follow-up at 12 months, whether in the active diet treatment group or standard care.  This is exceptional for this type of study, and it would be interesting to know if participants received incentives beyond the free diet products.  In this study, GPs used their discretion in assessing psychiatric issues or issues related to ability of commitment and so people were chosen who were more likely to be able to follow it through.  Typically in these types of studies subjects with eating disorders such as binge eating are excluded e.g. such as in the DiRECT study, however this is not particularly mentioned.

“While this study is not a study of people preparing for weight loss surgery, we’ve observed from clinical audit and observations that around 65% of patients within that setting have tried some form of radical dieting previously and all not just failed but are heavier as a consequence.  This phenomenon is clearly documented in research and something we describe as yo-yo dieting effect and weight rebound, or ‘post-starvation syndrome’.

“This study was supported through a grant from Cambridge Weight Plan UK, and participants received Cambridge Weight Plan products free of charge.  It is in principle testing the use of a commercial provider to provide the TDR/ meal replacement, the guidance on food reintroduction and weight maintenance and behaviour counselling for ongoing behavioural support up to 12 month which is the duration of this study.  Repeated courses (up to 4 weeks) of TDR were possible, so this is not a single one off or simple dietary intervention study.

“Many people reading this will ask themselves whether they should try one of these diets.  My answer is a clear not on your own, especially if it is understood as ‘a standalone diet’, as the evidence given here clearly shows the diet alone is much less effective than the diet combined with behavioural support.  Of course losing weight is good if you are overweight, but a large body of research indicates that the only way it will work is if using the programme as a means to future change, as a stepping stone to change eating habits for good.”

Dr Barbara McGowan, member of the Society for Endocrinology, Consultant Endocrinologist and lead for medical obesity services at Guys & St Thomas’ Hospital, said:

“This study provides extra support to the recently reported DIRECT trial in patients with Type 2 diabetes for the role of total diet replacement programmes delivered in primary care for the treatment of obesity.

“The trial is well designed and conducted, and the conclusions are robust.  This pragmatic study shows that the intervention is effective compared to usual care at 1 year, is acceptable to patients and is achievable within primary care.  It has the potential to be scaled up across the NHS if found to be cost-effective as a treatment for obesity.”

Declared interests

Dr Scott Harding: “I have no conflicts or other declarations of competing interests with regard to this study.”

Dr Katarina Kos: “No interest to declare.”

Dr Barbara McGowan: “No conflicts.”