At what level of estimated glomerular filtration rate (eGFR) and proteinuria is a decreased protein intake recommended?

From the Guidelines

Decreasing protein intake is recommended for patients with chronic kidney disease (CKD) when their estimated glomerular filtration rate (eGFR) falls below 30 mL/min/1.73m² (CKD stages 4-5) and/or when they have significant proteinuria, with the goal of limiting dietary protein to approximately 0.8 g/kg of body weight per day, as supported by the 2025 standards of care in diabetes 1.

Key Considerations

• The recommended daily allowance of 0.8 g/kg/day is advised for people with stages 3–5 non–dialysis-dependent CKD, as it slows GFR decline with evidence of a greater effect over time 1.
• Higher levels of dietary protein intake (>20% of daily calories from protein or >1.3 g/kg/day) should be avoided, as they have been associated with increased albuminuria, more rapid kidney function loss, and CVD mortality 1.
• Reducing dietary protein below the recommended daily allowance of 0.8 g/kg/day is not recommended, as it does not alter blood glucose levels, cardiovascular risk measures, or the course of GFR decline 1.
• Some organizations recommend a lower protein intake (0.6–0.8 g/kg/day) for reno-protection, but this is graded as "opinion" only for CKD in diabetes, and the evidence for lower protein intake in people with CKD has been published for only those without diabetes, which is graded Level 1A 1.

Implementation

• Patients should work with a healthcare professional experienced in managing nutrition for people with CKD to ensure adequate nutrition while restricting protein, as malnutrition is a concern with overly restrictive diets.
• Essential amino acids must still be obtained, and caloric intake should be maintained with non-protein sources.
• The protein restriction should be part of a comprehensive renal diet plan that also addresses sodium, potassium, phosphorus, and fluid intake as appropriate for the individual's specific kidney function.

From the Research

Decreasing Protein Intake Recommendations

• The recommendation to decrease protein intake is based on the level of estimated glomerular filtration rate (eGFR) and proteinuria, as stated in the study 2.
• A low-protein diet is recommended when eGFR falls below 60 mL/min/1.73 m2 or when there is solitary kidney or proteinuria at any level of GFR.
• Protein intake should be reduced progressively based on the severity and progression of chronic kidney disease (CKD) and the patient's nutritional status, with a target of 0.6-0.8 g/kg/d in most patients with eGFR <45 mL/min/1.73 m2, as suggested in the study 2.
• The study 3 found that in participants with impaired kidney function, a high dietary protein intake of ≥1.4 g/kg ABW/day was associated with higher mortality, while lower protein intake levels were not associated with mortality.

Protein Intake Levels

• A dietary protein intake below 1.0 g/kg/day is recommended when eGFR falls below 60 mL/min/1.73 m2 or when there is solitary kidney or proteinuria at any level of GFR, as stated in the study 2.
• The study 4 recommends a dietary protein intake of 0.8 g protein per kg body weight per day for a healthy adult with minimal physical activity.
• The study 5 recommends an average daily intake of at least 1.0 to 1.2 g protein per kilogram of body weight per day for older people to maintain and regain lean body mass and function.

Special Considerations

• The study 2 notes that low-protein diet is safe, since most CKD patients can maintain nitrogen balance by mechanisms of decreasing amino acid oxidation and protein degradation in addition to increased utilization of amino acids for protein synthesis.
• The study 5 recommends higher protein intake (i.e., ≥ 1.2 g/kg body weight/d) for older adults who are exercising and otherwise active.
• The study 5 also notes that older people with severe kidney disease (i.e., estimated GFR <30 mL/min/1.73 m2), but who are not on dialysis, may need to limit protein intake.