Life style. Functional bowel disorder, not anatomic or organic disease. Doesn't cause or lead to inflammatory bowel disease, celiac sprue, cancer, etc. Can co-exist with the above. Generally not cause weight loss, anemia, bleeding. Sx can interfere with day to day activities and diet. Discuss with doc re: options to stay healthy, active, and to make sure there is not something else causing the symptoms.
Metabolic imbalance. Irritable bowel syndrome is the multifactorial consequence of hormonal, immune system and nervous system dysfunction resulting from genetic predispositions and dietary and environmental insults. The predominant symptoms like diarrhea cramps constipation are the result of autonomic nervous system instability. Whatever is causing your ibs can also cause many other symptoms as well mdellnessmd, com.