The goal of this clinical trial is to determine whether increasing protein intake in elderly adults with pre-dialysis chronic kidney disease, in combination with resistance exercise, improves muscle mass without worsening renal function.The main questions it aims to answer are:

• Does a protein intake of 1.2 g/kg BW/day combined with exercise improve muscle mass better than a protein intake of 1.0 g/kg BW/day?
• Does a protein intake of 1.2 g/kg BW/day combined with exercise lead to greater improvements in muscle strength and function?
• Does a protein intake of 1.2 1.2 g/kg BW/day combined with exercise cause a decline in renal function (eGFR) compared to a protein intake of 1.0 1.2 g/kg BW/day?

Researchers will compare a group assigned to intake 1.2 g/kg BW/day of protein with another group assigned to intake 1.0 g/kg BW/day, to assess whether the higher intake improves muscle mass and physical performance without causing harm.

Participants will

• be assessed for body composition, physical performance and nutritional intake.
• be assigned to consume protein at either 1.2 or 1.0 g/kg/day.
• perform a home-based resistance exercise program using resistance bands.
• provide blood and urine sample to monitor renal function.
• visit the clinic at weeks 12 and 24 for repeated measurement.

Inclusion Criteria:

• Thai adults aged ≥ 65 years
• Chronic kidney disease with estimated glomerular filtration rate (eGFR) 30-59 ml/min/1.73 m2
• Sarcopenia or presarcopenia (diagnosis based on Asian Working Group for Sarcopenia (AWGS) 2019 definition)

Exclusion Criteria:

• Active cardiopulmonary disease(s) or uncontrolled hypertension with contraindications to resistance training
• Physically or cognitively unable to participate in the resistance exercise program (e.g. dementia), as determined by the attending physician
• Limitations of body measurements and interpretation using Bioelectrical Impedance Analysis (BIA) e.g. presence of pacemaker, surgical metal implants
• Meets the definition of AKI or AKD, defined as alterations in kidney function within the past 3 months
• Severe vitamin D deficiency (25-OH Vitamin D level < 10 ng/mL)
• Refuses to give consent to participate in the study