NIHR DC Discover

Low energy total diet replacement treatment

NIHR Signal A total diet replacement programme helped obese people lose weight and keep weight off

Published on 18 December 2018

doi: 10.3310/signal-000698

A programme of weekly behavioural support with total diet replacement led to over 7kg greater weight loss than usual care in primary care. This weight loss was maintained for a year after starting the 8-12 week low calorie programme.

This trial, funded by NIHR and a commercial sponsor, was carried out in ten primary care practices in Oxfordshire. Participants had BMI over 30. It referred half of the 278 participants to a commercial weight loss programme, free of charge for six months. The rest of the participants received usual care from their practice for 12 weeks.

Participants initially replaced all food with four formula food products daily (soups, shakes, and bars) containing 810 kcal per day. After eight weeks of this low calorie diet, conventional meals were gradually reintroduced.

This trial provides evidence that the rapid weight loss from these replacement diets can be maintained for a reasonable time and so could be considered as a treatment option for anyone who is obese and needs support to lose weight.

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Why was this study needed?

In 2016, 26% of adults in England were obese. Obesity can lead to several medical conditions, including heart disease, type 2 diabetes and some cancers. Losing weight reduces the health risks for individuals. Treatments include increasing physical activity, reducing calorie intake, weight-loss drugs, and weight-loss (bariatric) surgery.

There is already some evidence that very low energy diets (fewer than 800 calories a day) can help people to lose weight, and keep more weight off after a year. However, all these trials took place in specialist clinics or research centres. None was carried out in routine primary care.

The NHS does not routinely offer these very low energy diet programmes. This study looked at referral by GPs to a commercially-provided low energy diet delivered by replacing food-based meals, compared with usual support in primary care.

What did this study do?

The DROPLET randomised controlled trial recruited 278 obese adults (BMI over 30) who wanted to lose weight. Half (138) were assigned to the diet replacement programme, and 140 were given usual care and support in primary care.

Those referred to their local Cambridge Weight Plan UK counsellor met weekly for three months. For eight weeks participants consumed 810kcal per day from meal replacement products, 750ml of skimmed milk, 2.25 litres of water or other low or no energy drinks, and a fibre supplement. This was followed by a four-week reintroduction of usual meals. There was then a 12-week maintenance phase, with monthly support appointments.

The usual care group had a 12-week programme of support from practice nurses and received a booklet about losing weight.

This was a pragmatic trial which couldn’t control every aspect of care. Participants and clinicians were aware of which treatment they were receiving, but this type of trial reflects the real world better. No-one in the usual care group could be referred to the programme once enrolled.

What did it find?

  • People in the diet replacement group lost more weight by 12 months than the usual care group. The mean weight change was -10.7kg (standard deviation [SD] 9.6kg) in the diet replacement group, and -3.1kg (SD 7.0kg) in the usual care group. The adjusted difference in mean weight change between the diet replacement and usual care groups was -7.2kg (95% confidence interval [CI] -9.4 to -4.9kg).
  • More people in the diet replacement group had lost 5% of their baseline body weight at 12 months: 73% in the diet replacement group vs 32% in the usual care group (adjusted odds ratio [OR] 6.5, 95% CI 3.4 to 12.2). Similarly, 45% of the diet replacement group had lost 10% of their baseline body weight, compared to 15% of the usual care group (adjusted OR 4.9, 95% CI 2.4 to 9.9).
  • After 12 months, the diet replacement group had greater reductions in HbA1c, (adjusted difference ‑2.2mmol/mol, 95% CI -4.4 to 0.0mmol/mol). HbA1c is a measure of a person’s average blood glucose levels for the previous two to three months. Higher levels indicate type 2 diabetes.
  • Mild adverse events were common in both groups: 51% of people in the diet replacement group and 30% in the usual care group experienced at least one side effect. The most common of these in the diet replacement group were constipation, fatigue, headache and dizziness.

What does current guidance say on this issue?

NICE updated its guideline on the identification, assessment and management of obesity in 2014. It says that very low calorie diets of 800 kcal per day or less should not be routinely used to manage obesity. These very low calorie diets should only be considered for adults who need to lose weight rapidly, such as people who need surgery or who are seeking fertility services. People on such a diet should be given ongoing clinical support.

Low calorie diets of between 800 and 1,600 kcal per day can be considered, but NICE say that clinicians should be aware that they are less likely to be nutritionally complete.

What are the implications?

This trial shows that referral from GP practices to a community-based diet replacement programme is very effective in helping people who are obese to lose weight and is associated with other health improvements.

That these effects can be maintained in the longer term is an important finding and suggests that such programmes could be considered routinely for any adults who are obese, not just those who need to lose weight rapidly such as before surgery.

Ongoing support was a feature of the programme used in this trial. NHS funding for such programmes may not be available in all areas of the country. This trial should provide reassurance to those clinicians who are wary about supporting people who choose to use a total diet replacement programme because they are unfamiliar with the approach or have concerns about safety.

This trial used one particular commercial programme providing meal replacement with counselling and support. Similar programmes are available from other providers.

Citation and Funding

Astbury NM, Aveyard P, Nickless A et al. Doctor Referral of Overweight People to Low Energy total diet replacement Treatment (DROPLET): pragmatic randomised controlled trial. BMJ. 2018;362:k3760. 

This project was funded by the National Institute for Health Research Collaboration for Leadership in Applied Health Research and Care Oxford, and a research grant from Cambridge Weight Plan UK.

Bibliography

NHS Digital. Statistics on obesity, physical activity and diet – England, 2018 [PAS]. Leeds: NHS Digital; 2018.

NHS website. Obesity – treatment. London: Department of Health; 2016.

NICE. Obesity: identification, assessment and management. CG189. London: National Institute for Health and Care Excellence; 2014.

Why was this study needed?

In 2016, 26% of adults in England were obese. Obesity can lead to several medical conditions, including heart disease, type 2 diabetes and some cancers. Losing weight reduces the health risks for individuals. Treatments include increasing physical activity, reducing calorie intake, weight-loss drugs, and weight-loss (bariatric) surgery.

There is already some evidence that very low energy diets (fewer than 800 calories a day) can help people to lose weight, and keep more weight off after a year. However, all these trials took place in specialist clinics or research centres. None was carried out in routine primary care.

The NHS does not routinely offer these very low energy diet programmes. This study looked at referral by GPs to a commercially-provided low energy diet delivered by replacing food-based meals, compared with usual support in primary care.

What did this study do?

The DROPLET randomised controlled trial recruited 278 obese adults (BMI over 30) who wanted to lose weight. Half (138) were assigned to the diet replacement programme, and 140 were given usual care and support in primary care.

Those referred to their local Cambridge Weight Plan UK counsellor met weekly for three months. For eight weeks participants consumed 810kcal per day from meal replacement products, 750ml of skimmed milk, 2.25 litres of water or other low or no energy drinks, and a fibre supplement. This was followed by a four-week reintroduction of usual meals. There was then a 12-week maintenance phase, with monthly support appointments.

The usual care group had a 12-week programme of support from practice nurses and received a booklet about losing weight.

This was a pragmatic trial which couldn’t control every aspect of care. Participants and clinicians were aware of which treatment they were receiving, but this type of trial reflects the real world better. No-one in the usual care group could be referred to the programme once enrolled.

What did it find?

  • People in the diet replacement group lost more weight by 12 months than the usual care group. The mean weight change was -10.7kg (standard deviation [SD] 9.6kg) in the diet replacement group, and -3.1kg (SD 7.0kg) in the usual care group. The adjusted difference in mean weight change between the diet replacement and usual care groups was -7.2kg (95% confidence interval [CI] -9.4 to -4.9kg).
  • More people in the diet replacement group had lost 5% of their baseline body weight at 12 months: 73% in the diet replacement group vs 32% in the usual care group (adjusted odds ratio [OR] 6.5, 95% CI 3.4 to 12.2). Similarly, 45% of the diet replacement group had lost 10% of their baseline body weight, compared to 15% of the usual care group (adjusted OR 4.9, 95% CI 2.4 to 9.9).
  • After 12 months, the diet replacement group had greater reductions in HbA1c, (adjusted difference ‑2.2mmol/mol, 95% CI -4.4 to 0.0mmol/mol). HbA1c is a measure of a person’s average blood glucose levels for the previous two to three months. Higher levels indicate type 2 diabetes.
  • Mild adverse events were common in both groups: 51% of people in the diet replacement group and 30% in the usual care group experienced at least one side effect. The most common of these in the diet replacement group were constipation, fatigue, headache and dizziness.

What does current guidance say on this issue?

NICE updated its guideline on the identification, assessment and management of obesity in 2014. It says that very low calorie diets of 800 kcal per day or less should not be routinely used to manage obesity. These very low calorie diets should only be considered for adults who need to lose weight rapidly, such as people who need surgery or who are seeking fertility services. People on such a diet should be given ongoing clinical support.

Low calorie diets of between 800 and 1,600 kcal per day can be considered, but NICE say that clinicians should be aware that they are less likely to be nutritionally complete.

What are the implications?

This trial shows that referral from GP practices to a community-based diet replacement programme is very effective in helping people who are obese to lose weight and is associated with other health improvements.

That these effects can be maintained in the longer term is an important finding and suggests that such programmes could be considered routinely for any adults who are obese, not just those who need to lose weight rapidly such as before surgery.

Ongoing support was a feature of the programme used in this trial. NHS funding for such programmes may not be available in all areas of the country. This trial should provide reassurance to those clinicians who are wary about supporting people who choose to use a total diet replacement programme because they are unfamiliar with the approach or have concerns about safety.

This trial used one particular commercial programme providing meal replacement with counselling and support. Similar programmes are available from other providers.

Citation and Funding

Astbury NM, Aveyard P, Nickless A et al. Doctor Referral of Overweight People to Low Energy total diet replacement Treatment (DROPLET): pragmatic randomised controlled trial. BMJ. 2018;362:k3760. 

This project was funded by the National Institute for Health Research Collaboration for Leadership in Applied Health Research and Care Oxford, and a research grant from Cambridge Weight Plan UK.

Bibliography

NHS Digital. Statistics on obesity, physical activity and diet – England, 2018 [PAS]. Leeds: NHS Digital; 2018.

NHS website. Obesity – treatment. London: Department of Health; 2016.

NICE. Obesity: identification, assessment and management. CG189. London: National Institute for Health and Care Excellence; 2014.

Doctor Referral of Overweight People to Low Energy total diet replacement Treatment (DROPLET): pragmatic randomised controlled trial

Published on 26 September 2018

N Astbury, P Aveyard, A Nickless, K Hood,K Corfield, R Lowe, S Jebb

BMJ Open , 2018

Objective To test the effectiveness and safety of a total diet replacement (TDR) programme for routine treatment of obesity in a primary care setting. Design Pragmatic, two arm, parallel group, open label, individually randomised controlled trial. Setting 10 primary care practices in Oxfordshire, UK. Participants 278 adults who were obese and seeking support to lose weight: 138 were assigned to the TDR programme and 140 to usual care. 73% of participants were re-measured at 12 months. Interventions The TDR programme comprised weekly behavioural support for 12 weeks and monthly support for three months, with formula food products providing 810 kcal/day (3389 kJ/day) as the sole food during the first eight weeks followed by reintroduction of food. Usual care comprised behavioural support for weight loss from a practice nurse and a diet programme with modest energy restriction. Main outcome measures The primary outcome was weight change at 12 months analysed as intention to treat with mixed effects models. Secondary outcomes included biomarkers of cardiovascular and metabolic risk. Adverse events were recorded. Results Participants in the TDR group lost more weight (−10.7 kg) than those in the usual care group (−3.1 kg): adjusted mean difference −7.2 kg (95% confidence interval −9.4 to −4.9 kg). 45% of participants in the TDR group and 15% in the usual care group experienced weight losses of 10% or more. The TDR group showed greater improvements in biomarkers of cardiovascular and metabolic risk than the usual care group. 11% of participants in the TDR group and 12% in the usual care group experienced adverse events of moderate or greater severity. Conclusions Compared with regular weight loss support from a practice nurse, a programme of weekly behavioural support and total diet replacement providing 810 kcal/day seems to be tolerable, and leads to substantially greater weight loss and greater improvements in the risk of cardiometabolic disease

Expert commentary

This research provides health care practitioners and policymakers with a better understanding of patients’ acceptability of low calorie diets, the safety of such approaches and how they can help obese adults work towards a healthier weight.

It reaffirms how important behavioural change is to achieving a healthier weight and that low calorie diet approaches, like other weight management approaches, need to help people set achievable goals and put in place strategies to solve challenges they may encounter.

Getting the right level of care and support to people living with obesity and wanting to lose weight is essential – this research aids understanding of the role of medically supervised low calorie diets.

Jamie Blackshaw, Team Leader: Obesity and Healthy Weight, Diet, Obesity and Physical Activity Division, Health Improvement Directorate, Public Health England

The commentator declares no conflicting interests