Recent studies have shown that for some people who live with obesity and type 2 diabetes, a low calorie diet can help them lose weight, reduce their risk of heart disease, and put their diabetes into remission.

The NHS wants to test whether or not a low calorie diet can be used to support patients in 10 areas in England. Eligible patients in these areas will receive low calorie meal replacement products (e.g. bars, shakes, soups) and ongoing support to help manage their eating. The support aspect will be delivered and tested in three different ways: digital technology, face to face group support, or face to face one to one support.

• Whether the low-calorie diet programme that has been tested in studies can work as well when delivered as part of the NHS, in helping patients to lose weight and improve their diabetes;
• What patients perceive to be the benefits and disadvantages of the programme;
• How much it costs the NHS, whether there are any costs to patients, and if so, if this a barrier to them completing the programme;
• Which method of support (1:1, group or digital) do patients prefer;
• What patients and staff involved in the programme think about it;
• Whether the programme is being delivered as it is intended (e.g. whether all eligible patients are being invited to receive the programme, whether patients are able to follow it as required, which eligible patients are not using the programme, or are having difficulty following it, and why).
• Whether the programme should be made available to every area across England, and if so, are any changes to the programme required before this happens.

1. We will talk to NHS staff involved with the programme, and to staff who will be delivering the programme, to ask them for their views about what has worked well, what has not, and why.
2. We will ask all patients who have been referred to the programme to complete a short survey to ask for their views about the programme.
3. We will take a detailed look at the lived experiences of a small sample of patients from different backgrounds and areas. This will involve talking to patients and asking them to take photographs or video diaries to document their journey.
4. We will look at how much the programme costs to run for the NHS, patients and any supporting organisations, and whether it offers value for money.
5. We will look at whether it is feasible to make the programme available across England.

This study will be carried out by a team of experts in weight management, diabetes and programme evaluation. The team also includes an expert patient panel, who will be involved throughout, in co-designing the study, liaising with patients, collecting data and helping to share the findings. We will also work closely with NHS England who are organising the programme for the 10 areas and collecting data on the patients’ weight and health.

We will share learning from this study in a number of different ways. This will include: writing reports for NHS England and academic papers, giving presentations at local and international events, producing short films and illustrated journals describing what we did, what we found and how the findings will be used, and sharing learning through this website.