Structured Weight Management Program for Diabetes REmission Clinical Trial-Australia – (DiRECT-Aus Study)

The intervention has three phases. Phase one is a 3400kJ (800kcal)/day Total Diet Replacement (TDR) using a commercial micronutrient-replete meal replacement product OPTIFAST, followed for 13 weeks. Phase two is a stepped food reintroduction during which meal replacement products will be replaced with low fat meals administered in three steps over 2-8 weeks. Starting at week 13, participants will replace one Optifast VLED product per day with one low fat meal (Step 1) which will be followed for a period of one to two weeks before replacing another Optifast VLED product with another low fat meal (Step 2) and again for Step 3. The timing of the Steps 1-3 of food reintroduction will determined by the participant and dietitian. Irrespective of the timing of Food Reintroduction, all participants will commence food reintroduction at Week 13 and remain on Step 3 of food Reintroduction until Week 21. Phase three is a weight maintenance diet during which participants will be provided with an individually tailored calorie prescription to support weight maintenance based on the Australian Guide to Healthy Eating with a target of <30% energy from fat and no more than 35% energy from fat. . These meal plans are intended to act as a guide and as participants become more confident and learn new skills they will be encouraged to self-manage. Diet goals will be discussed and agreed upon with the dietitian. . Throughout the entire study participants will receive education on behavioural weight management through a structured program delivered by dietitians with experience in supporting behaviour change. Participants will meet with the dietitian every 2 weeks in the first 17 weeks of the study and then every month until week 52 and a new topic in behavioural weight management will be discussed at every visit supported by a participant workbook. . Throughout the entire 12 months of the study participants will also be supported to increase their physical activity levels. Participants are encouraged to include physical activity in line with the Australian Physical Activity Guidelines, including 150 minutes per week of moderate intensity physical activity, muscle strengthening activities on two days each week and limiting sitting time. As participants physical fitness improves, participants are encouraged to increase physical activity aiming for 10,000 – 15,000 steps/day. Modules on physical activity will be delivered within the behavioural weight management program at visits 3, 5, 8 and 18 and included in the participant workbook. Steps counts (on the participants mobile phone) will be used to track activity and increase motivation where available. During the weight maintenance phase, rescue package will be offered to any participant who regains >2 kg or experience re-emergence of diabetes. For weight regain of 2-4 kg participant will be offered the use of Optifast to replace one main-meal per day for 4 weeks. For weight regain of >4kg or reemergence of diabetes, participants will be offered 4 weeks VLED with fortnightly practice nurse/dietitian review followed by a 2-4 week food re-introduction (add 1 meal/day/ week). The Optifast meal replacements are free and at no cost to the participants. Participants will continue to receive standard care under current clinical guidelines for T2DM. Intention to treat analysis will be conducted, with follow-up data continuing to be collected even if treatment is stopped. The intervention will be delivered in primary care practices by practice nurses/dietitians (according to local availability and practice) with training, support and mentoring from the Diabetes NSW & ACT and The Boden Collaboration, University of Sydney. The frequency and duration of study visits that participants will attend as part of the intervention' Participants will attend a minimum of 20 visits, with additional visits possible for the delivery of rescue packages. Visits may take up to 60 minutes. All participants will return one week after screening for review, and then once every two weeks until week 17. After week 17, participants will attend once month, unless a rescue package is used. Visits 1,2,3,5,7,8,10,11, 12, 14,16,18,19 are intended to be performed as one on one sessions and visit 4,6,9,13,15,17,20 are intended to be performed as group sessions, with flexibility to facilitate safe and convenient delivery as per local conditions. Telephone visits with the dietitian may also be used where required, although participants will need to attend to have measurements taken as per the visit scheduled outlined above.