Drug–nutrient interaction is an important consideration in the nutritional management of Parkinson’s disease because both the disease and its medications can significantly influence food intake, nutrient absorption, metabolism and utilization. Parkinson’s disease is a progressive neurological disorder characterized by tremor, rigidity, bradykinesia and postural instability. Levodopa, often administered with carbidopa, is the main pharmacological treatment. The effectiveness of therapy can be affected by dietary factors, particularly protein intake. Levodopa is an amino-acid-like compound that uses the same transport system as dietary large neutral amino acids. Therefore, a high-protein meal may compete with levodopa for absorption from the intestine and transport across the blood–brain barrier. Consequently, some patients may experience reduced or delayed therapeutic effects after consuming protein-rich meals. Foods such as meat, fish, eggs, milk and pulses are major sources of protein and may influence medication response. This does not mean that protein should be eliminated, because adequate protein is essential for maintaining muscle mass and preventing malnutrition. Instead, protein intake may be distributed more