Testing the Effectiveness of a Low Carbohydrate Diet With Remote Support for Patients With Type 2 Diabetes in Primary Care, on Weight and Glycaemic Control: a Randomised Controlled Trial

This is an individually randomised controlled trial. Participants, recruited via GP practices, will be randomised 1:1 with simple randomisation and no stratification to either the intervention group or control (usual care). They will be enrolled in the study for 1 year, of which the intervention (dietary support via the app) will run for 3 months. Most study procedures will be conducted online or remotely (by telephone) including: screening, eligibility assessment, informed consent, randomisation, engagement with the app-based intervention. Participants will be asked to attend 3 face to face appointments for the research study at their local GP practice for measurements to be taken (weight, blood pressure) and blood tests, at baseline, 3 months and 1 year, and will have 1 additional telephone contact with their GP or practice nurse before starting the intervention. Face to face appointments will be incorporated with routine clinical appointments when possible.

The investigators aim to recruit 100 participants via their GP practices. Based on a conservative response rate of 10% from similar previous studies, the investigators will approach approximately 1000 eligible individuals from approximately 10 GP practices in England. The primary care provider will search their electronic registers for eligible individuals and GPs will screen out those to whom it would be inappropriate to send a letter inviting them to enrol and referring them to a website to give informed consent.

Once consent has been given, participants will click on a link to the electronic data capture system database which will be activated following their consent, to complete the baseline assessment. All participants will complete a 2 part baseline assessment, firstly online and then at their GP practice.

1. Online:

Participants will be asked to complete a baseline questionnaire requesting demographic information and their current medication, and the standard questionnaires that will be used in the study (the Problem Areas in Diabetes (PAID) score, the EQ5D (quality of life assessment), and a 24 hour dietary recall questionnaire ("Intake24 dietary assessment tool", where participants are asked to record all food and drink intake in the last 24 hours). This will also further assess whether people are sufficiently able to complete online trial procedures, and only those who complete the questionnaire will be randomised. Participants will be informed in the Participant Information Sheet that they will only be able to enter the study after completing the questionnaire fully in one attempt as the system will not allow them to go back into the questionnaire to answer the remaining questions later. This should take less than 30 minutes to complete. 2. At the GP practice (visit 1) Having completed the online assessment, participants will be asked (via message on their screen on completing the assessment, and followed up via email) to book the in-person portions of their baseline assessment at their GP practice for measures which cannot be conducted online. At this appointment, their height, weight and blood pressure will be measured and recorded, and a blood sample taken for baseline values (HbA1c, lipid profile, liver function tests).