There are numerous possible causes of constipation. Lack of fiber in the diet Not getting enough dietary fiber may lead to constipation. This is because fiber promotesTrusted Source regular bowel movements, especially when a person combines it with proper hydration. Examples of high fiber foods include: fruits vegetables whole grains nuts lentils, chickpeas, and other legumes Learn about foods that may be good for treating constipation. Physical inactivity Low levels of physical activity or not getting enough exercise may also lead to constipation. Researchers do not know exactlyTrusted Source why not getting enough physical activity can cause constipation. However, they believe it may be because physical activity helps stool pass through the colon. Certain medications Some medications can increase the risk of constipation. These include: anticonvulsants antacids containing calcium and aluminum anticholinergics antispasmodic diuretics calcium channel blockers narcotic pain medications diuretics It is best for a person to contact a doctor if they believe medication they are taking may be causing constipation. Medical conditions Some medical conditions can cause or increase a person’s risk of constipation. These include: irritable bowel syndrome and other functional gastrointestinal disorders anxiety, depression, or stress celiac disease Parkinson’s disease diabetes and other conditions that affect metabolism hypothyroidism and other conditions that affect hormones inflammation due to proctitis or diverticular disease intestinal obstruction Treating the underlying medical condition may help alleviate symptoms of constipation. Other causes Other possible causes of constipation include: not drinking enough water changes in bowel movements as a person ages laxative overuse or abuse