Plant-dominant low-protein diet versus standard care in adults with chronic kidney disease stages 3–5: A randomized controlled trial protocol

Background The plant-dominant low-protein diet (PLADO), providing 0.6-0.8 g/kg/d of protein with ≥50% derived from plant sources, may improve acid–base balance and metabolic outcomes in chronic kidney disease (CKD). However, concerns remain regarding safety and feasibility, and experimental evidence is limited. Objective This protocol describes a randomized controlled trial (RCT), designed to evaluate the efficacy, nutritional and biochemical safety, implementation feasibility, and cost-effectiveness of PLADO compared with the standard renal diet in adults with CKD stages 3-5. Methods This unblinded, parallel-group RCT will enroll 48 adults with CKD stages 3-5 in a medical center in Lebanon and randomize participants 1:1 to PLADO or standard-of-care renal diet for 6 months, followed by a 3-month free-living phase. Both groups will receive monthly individualized dietary counselling. Outcomes The primary outcome is change in metabolic acidosis between groups, assessed by plasma total CO₂ from baseline to 6 months. Improvements in acid–base status are hypothesized to result from reduced dietary acid load, increased fiber intake, and favourable gut microbiota–related metabolic changes. Secondary outcomes include biochemical markers (uremia and anemia markers, electrolytes), nutritional status (GLIM criteria), gastrointestinal symptoms, quality-of-life (EQ-5D-5 L), gut microbiota composition, and cost-effectiveness. A mixed methods process evaluation will assess intervention fidelity, adherence, and reach. Expected Contribution This trial will provide experimental evidence on the efficacy, safety, and feasibility of PLADO in the conservative management of CKD stages 3-5, informing dietary practice in resource-limited settings, where healthcare delivery is challenged by limited insurance coverage and economic instability.