Korean culture and health related beliefs and practices...?

In the Korean culture what do they believe promotes health (e.g., eating certain foods, wearing amulets to bring good luck, exercise, prayer, rituals to ancestors, saints or intermediate deities)? Do they rely on cultural healers? Who determines when they are sick and when healthy and who determines the type of healer and treatment that should be sought? Please answer in regards to each question and preferably you are of the Korean culture or an expert in the field. Thank you