Plant-Dominant Low-Protein Diet versus Standard Care in Adults with Chronic Kidney Disease Stages 3–5: A Randomized Controlled Trial Protocol

• PLADO: plant-dominant low-protein diet for CKD management. • First RCT testing PLADO in CKD patients • PLADO may improve metabolic acidosis • Evaluates PLADO safety, feasibility, adherence, and quality of life in CKD • Includes gut microbiota and cost-effectiveness assessments of PLADO. The plant-dominant low-protein diet (PLADO), providing 0.6–0.8 g/kg/day 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. 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 standard renal diet in adults with CKD stages 3–5. This unblinded, parallel-group RCT will enroll 48 adults with CKD stages 3–5 in a medical centre in Lebanon and randomize participants 1:1 to PLADO or standard-of-care renal diet for six months, followed by a three-month free-living phase. Both groups will receive monthly individualized dietary counselling. 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 fibre 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-5L), gut microbiota composition, and cost-effectiveness. A mixed methods process evaluation will assess intervention fidelity, adherence, and reach. 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. NCT06932042 The graphical abstract illustrates the randomized controlled trial comparing a PLADO diet with a standard renal diet in 48 adults with CKD stages 3–5. Participants receive monthly counseling over a 6-month intervention followed by a 3-month free-living phase. The primary outcome is metabolic acidosis (plasma total CO₂); secondary outcomes include biochemical markers, nutritional status (GLIM), gastrointestinal symptoms, quality of life (EQ-5D-5L), gut microbiota, and cost-effectiveness. Abbreviations: PLADO = plant-dominant low-protein diet (0.6–0.8 g protein/kg/day, ≥50% plant-based, high fiber, low sodium, adequate calories), CKD = Chronic kidney disease, N: 48; 1:1 = total participants 48 with permuted block randomization design with an allocation ratio of 1:1.