Hi, this is called gustatory rhinintis which is runny nose after eating certain foods . Usually its spicy foods but it can be a variety of those with preservatives or dyes , hot or cold. This is caused when the blood vessels of the nose are dilated and can produce clear, watery discharge after the ingestion of food. You can try taking an antihistamine (over the counter) once a day, one hour before eating. If you can avoid foods with preservatives and spicy foods. Also , if these dont work please make sure you tell your doctor .
Have a good day.