Intermittent Low Energy Diet in CKD: MIX UP Feasibility Study (MIX-UP)

Model of Intermittent Very Low Energy Diet and eXercise for Lowering BMI in Patients With CKD (MIX UP): Feasibility Study

This study proposes to investigate the acceptability and efficacy of intermittent VLED (5:2 diet) plus exercise, compared with the investigator's established Weight Management Programme (WMP), in obese patients with CKD, using feasibility study methodology. Patients will be invited to participate in the parallel arm, single blinded, randomised controlled feasibility study, and randomly allocated to 1 of 2 treatments for 6 months. The experimental arm involves an intermittent modified fasting regimen consisting of VLED (600 kcal/day) on 2 consecutive days, and 5 days each week on a modified diet to maintain an overall energy deficit of 600 kcal/day across the week (5:2 diet). The control arm will be the standard renal WMP with a continuous energy restricted diet aimed at reducing daily energy intake by 600 kcal/day. The feasibility outcomes are: recruitment rate >50%; intervention retention rate at 6 months >60%; dietary intervention compliance; and weight loss. Secondary outcomes include safety, body composition, proteinuria, lipids, blood pressure, and eating desire. Measurements will be made at baseline, midpoint, and twice at endpoint.

The intervention arm will involve standard care plus an intermittent modified fasting regimen consisting of a very low energy diet (600 kcal/day) on 2 consecutive days of the week, and 5 days each week on an energy restricted diet to maintain a similar overall energy deficit of 600 kcal/day across the week (5:2 diet). All dietary intake on modified fasting days will be from LighterLife foodpacks, (4 x 150 kcal portions/day presented as milkshakes, cereal bars, soups and modified meals such as spaghetti bolognese, or macaroni cheese) providing ~600 kcal/day and 100% of the RNI for vitamins and minerals.

Renal Weight management Programme - Patients will attend individual appointments with the specialist dietitian and physiotherapist once a month, for 6 months. Dietary intervention includes a standard continuous energy restricted diet aimed at reducing daily energy intake by 600 kcal/day relative to their estimated total energy expenditure (9). In addition to the dietary intervention, the programme also includes personal exercise plans, optional pharmacotherapy (orlistat at standard dose), and development of personalised dietary and exercise goals using behavioural therapy techniques and motivational interviewing.

very low energy diet (600 kcal/day) on 2 consecutive days of the week, and 5 days each week on an energy restricted diet to maintain a similar overall energy deficit of 600 kcal/day across the week (5:2 diet)

Dietary intervention includes a standard continuous energy restricted diet aimed at reducing daily energy intake by 600 kcal/day relative to their estimated total energy expenditure. In addition to the dietary intervention, the programme also includes personal exercise plans, optional pharmacotherapy (orlistat at standard dose), and development of personalised dietary and exercise goals using behavioural therapy techniques and motivational interviewing.

Patients attending at least 80% of monthly clinic visits, including the baseline and final study visits, and remaining compliant with the 2 consecutive days VLED throughout the 6 month intervention will be considered "completers" and count as being retained in the intervention group at 6 months.

record of all adverse events including but not limited to nausea, constipation and/or diarrhoea, dehydration, hypoglycaemia, lethargy & fatigue, headaches, gallstones and gout.

at least 50% of those meeting the referral criteria and are approached to participant, consent to participating in the study

Inclusion Criteria: aged 18-75 years KDIGO defined CKD (all categories) BMI ≥30kg/m2 able to provide written informed consent in English Exclusion Criteria: pregnant or breastfeeding women conservatively managed CKD stage 5 palliative or active treatment for cancer unstable chronic liver disease type 1 diabetes and type 2 diabetes controlled with anti-hyperglycaemic medication previous bariatric surgery unable to provide written informed consent significant psychiatric disorder or uncontrolled depression participated in a weight management drug trial in the previous 3 months uncontrolled epilepsy alcohol or substance abuse