My 50 yr old sister says all soda causes her diarrhea.and says its the color of whatever soda she happens to drink.what could be the cause? diabetes?

Sodas are unhealthy: Figure that there are 4 grams of sugar per teaspoon. That means nearly 12 teaspoons of sugar in that bottle of Coke, nearly 7 teaspoons of sugar in the smaller can of Pepsi. Re your sister, she is 50 years old. She needs to take better care of her health. Start with a full check up by a doctor including all the recommended blood work and other exams. Stopping soda is also a good idea.

Prob not diabetes: Does not sound like this would be caused by diabetes. However, the easy solution is to avoid sodas that cause the problem