Diarrhea is a common condition and often lasts for a short period of time. Diarrhea can occur many times a year.. This is a condition of having more frequent bowel movements with at least 3 loose stools within 24 hours. Diarrhea can be caused by many factors, and some foods like yogurt can control or aggravate it. So the question is: Should you eat yogurt when having diarrhea?