<human>:  What type of diet would be most suitable for a marathon runner?
<bot>: The most suitable diet for a marathon runner would be a balanced diet that is high in carbohydrates, lean proteins, and healthy fats. It should also include plenty of fruits and vegetables and adequate hydration. Additionally, it is important to adjust the diet according to the marathoner's training intensity and duration to ensure they get enough energy and nutrients to support their performance.