In this pilot clinical trial, the investigators will recruit and randomize 120 patients with diabetes mellitus and chronic kidney disease (CKD/DM) stages 3 to 5 to a patient-centered and flexible Plant-Focused Nutrition in Diabetes (PLAFOND) diet with >2/3 plant-based sources, which will be compared with a standard-of-care CKD diet, which is usually a low-potassium and low-salt diet, over a 6-month period. Through this study, the investigators will determine whether the plant-focused diet intervention is feasible for patient adherence, whether this diet is safe by avoiding malnutrition, frailty, and high potassium or glucose blood levels, and whether patient reported outcomes are favorably impacted.

Chronic kidney disease (CKD) affects 10-15% of US adults including 30-40% of persons with diabetes mellitus (DM), is associated with poor outcomes, and often progresses to requiring dialysis or transplantation. Half of all Americans with CKD also have DM. While traditional and emerging pharmacotherapies are often used in CKD with diabetes (CKD/DM), the synergistic role of dietary interventions has not been well examined. Low-carbohydrate low-fat diets are often recommended in DM, whereas low-protein diets (LPDs) are recommended for non-diabetic CKD with increasing emphasis on plant-based protein sources. Evidence suggests that high-protein diets with greater animal protein content may lead to glomerular hyperfiltration and faster decline in renal function in patients with CKD/DM. There remains major controversy regarding the potential risks vs. benefits of plant-based diets in CKD/DM, for which guidelines remain based on expert opinion. Given conventional dietary restrictions for the management of DM, there is concern that plant-based LPDs may lead to protein-energy wasting and hyperkalemia, whereas these diets may indeed be most beneficial in patients with CKD/DM given their faster rates of CKD progression as compared to non-diabetics. At present, clinical practice guidelines provide conflicting recommendations regarding the amount (low vs. high) and source (plant vs. animal) of dietary protein intake (DPI) in CKD/DM. Given that prior dietary trials in CKD such as the 1994 Modification of Diet in Renal Disease (MDRD) study excluded CKD/DM and did not examine the optimal proportion of plant vs. animal-based proteins, there is urgent unmet need for a rigorous dietary intervention study to examine the efficacy and safety of patient-centered plant-based diets in CKD/DM.

The investigators will conduct a pilot feasibility randomized controlled trial in parallel with patients' routine follow-up visits at ambulatory clinics to test the feasibility and safety of implementing a Plant- Focused Nutrition in CKD/DM (PLAFOND) diet with a DPI of 0.6-0.8 g/kg/d comprised of >2/3 plant-based sources, vs. standard-of-care renal diet with <1/3 plant-sources and low-potassium content, administrated by dietitians, over a 6-month period in 120 patients with CKD/DM stage 3-5. The investigators will determine whether the PLAFOND diet vs. the standard-of-care renal diet can be adhered to with consistent separation in dietary protein and plant-based proportions at 3- and 6-months. The investigators will also examine nutritional status, physical performance, and body composition, as well as glycemic measures using traditional metrics and continuous glucose monitoring, while other biochemical parameters and patient-reported outcomes including CKD-related symptoms will also be studied. In addition to providing the requisite feasibility and safety data of patient-conduct of future multi-center trials, this study will have major immediate impact by reinvigorating the critical role of dietary management of CKD/DM.

Inclusion Criteria:

• Adult outpatient (>18 years old) with diabetes mellitus (DM), who attends ambulatory clinics in one of the two centers, who has the established diagnosis of stage 3-5 CKD and DM regardless of degree of proteinuria, and who wishes to prevent or delay dialysis initiation, is qualified, as long as there are at least 2 eGFRs <60 ml/min/1.73m2 three months apart with no intervening higher eGFR values.
• Participants will agree to follow the dietary instructions based on the randomization assignment and attend baseline visits as well as three additional ambulatory visits on Month 1, 3 and 6 post-randomization in person or via telehealth and respond to monthly or more frequent phone calls.

Exclusion Criteria:

• Having a terminal illness with a life expectancy <6 months such as stage 4 metastatic cancer.
• Patients with any serum potassium >5.5 mEq/L during the 6 months preceding the screening visit.

Meal plans in both arms will be administrated by the study dietitians over 6-months among 120 patients with non-dialysis CKD/DM stages 3-5 for 6-months to examine dietary, nutritional, and glycemic endpoints.