1. Irritable Bowel Syndrome (IBS)

Seattle-based registered dietitian and nutritionist Angel Planells says that people with IBS are not recommended to drink black coffee.

IBS is a digestive disorder that affects the large intestine. IBS often causes symptoms such as abdominal pain, abdominal cramps, bloating, diarrhea or constipation.

"Caffeine can increase bowel regularity, including increasing the likelihood of diarrhea, a major symptom of irritable bowel syndrome," she said, as reported by Eat This Not That (2/12/2022).