Metabolic acidosis is a common complication in chronic kidney disease (CKD) and is associated with accelerated disease progression. Diets with a low potential renal acid load (PRAL) represent a promising non-pharmacological strategy to mitigate metabolic acidosis. The New Nordic Renal Diet (NNRD), a plant-focused, low-phosphorus diet, improves acid-base status in patients with CKD stage 3–4. This study evaluated the effects of a two-week, low-PRAL modified NNRD in patients with advanced CKD and chronic metabolic acidosis.