This two-year follow up, single-center, open-label, feasibility study will recruit outpatients from the Renal Medicine Clinic at Changi General Hospital. Eligible patients with Stage 3 or 4 CKD will be assigned preferencebased to either a plant-based diet intervention (intake of at least 50% protein from plant sources) with regular dietitian counselling and follow up, or a control group receiving dietitian counselling for general CKD dietary advice without information on percentage of plant-based foods. Six monthly assessments will include estimated glomerular filtration rate (eGFR), serum potassium, nutritional markers, and other relevant biochemical parameters. Quality of life and dietary adherence will be evaluated through questionnaires and food frequency records. This study will evaluate primarily, the feasibility of a plant-based diet in the Singaporean context. Secondarily it will evaluate its safety in terms of incidence of hyperkalaemia, and benefit in terms of improvement in acidosis.

Other exploratory outcomes will include (1) preliminary efficacy of plant-based diets on CKD progression (measured by eGFR decline); (2) risk of nutritional deficiencies such as vitamin D, B12 and iron; and (3) impact on other biochemical parameters of CKD.

Inclusion Criteria:

1. Age 21-79 (Only adults who can give consent will be recruited. Older adults aged 80 are not included to reduce the risk of confounding due to age-related frailty, sarcopenia and multimorbidity. Additionally, older adults may have different nutritional needs and energy requirements)
2. CKD stage 3-4 (baseline eGFR 15-60ml/min/1.72m2 for the past 6 months)
3. Willingness to see a dietitian and follow either a standard CKD diet or a predominantly plant-based CKD diet
4. On maximum tolerated dose of ACE-inhibitors (Angiotensin converting enzyme inhibitors) or ARB (Aldosterone receptor blocker) as determined by Renal Physician in charge
5. Able to provide informed consent

Exclusion Criteria:

• Transplant patients (who will tend to have more variable trajectories, immunosuppression related challenges etc which may make this study less feasible)
• Pregnant or lactating patients (who have different nutritional requirements than the standard CKD patients)
• Patients who were on any special diet for at least 1 month prior to recruitment (inclusive of
• long-term vegans or vegetarians) - excluded because they already have stable dietary habits
• Age <21 or >/= 80 (Avoid growing children who have different nutritional requirements and advanced elderly who are more likely to have malnutrition or sarcopenia due to other pre-existing causes)
• Those who have seen a dietitian for CKD previously
• Patients with severe ischemic heart disease, decompensated liver cirrhosis, malabsorptive diseases or malignancy
• Patients with BMI <18.5 or >40
• Patients with glomerulonephritis, genetic kidney disease or polycystic kidney disease
• Baseline serum potassium 5.0 and above
• Patients who are unable to modify their diet due to socio-economic issues.
• Exclude patients with acute kidney injury (AKI) in the past 6 months prior to study (unstable renal disease

Individual participant data (IPD) sharing is currently undecided. A data sharing plan will be developed at a later stage in accordance with institutional policies and applicable regulations.