Korean culture and nutrition?

In the Korean culture do religious beliefs and practices influence the diet (e.g., amount, type, preparation or delineation of acceptable food combinations, such as kosher diets)? Do they abstain from certain foods at regular intervals, on specific dates determined by the religious calendar, or at other times? If the religion mandates or encourages fasting, what does the term "fast" mean (e.g., refraining from certain types or quantities of foods, eating only during certain times of the day)? For what period of time are they expected to fast? Please answer in relation to all questions and preferably you are of the Korean culture or are an expert in the field. Thank you.