What Happens in Your Body When You're Constipated

Each year approximately 2.5 million people in the United States see a doctor for constipation. While the frequency and severity of constipation varies greatly, the underlying cause is the same: waste product moving abnormally slow through the large intestine. The result is that bowel movements are less frequent and irregular.

But exactly what does it mean to be "regular," and what happens in your body when this occurs? I'm breaking down this common bathroom issue along with three of the most effective habits for prevention.

What Does It Mean to Be "Regular"?

The clinical definition for constipation is having less than three bowel movements a week. The problem with this definition though is that the frequency that each individual usually "goes" varies greatly. While some individuals may typically have one to two bowel movement a day, the norm for others may be three to four bowel movements a week. Because of this, many health professionals prefer to define constipation as when one strays significantly from their normal bathroom pattern, or when bowel movements are hard and may require straining. (Learn more about 10 sneaky signs you could be constipated, according to a gut health doctor.)

What Goes Wrong in the GI Tract?

Let's start at the beginning with the basics of digestion and what happens when you eat. Food and drink enter the digestive tract and begin their progression through the esophagus to the stomach once swallowed. Gastric juice and enzymes in the stomach start the digestive process until the contents move to the small intestine. The contents move to the small intestine where enzymes finish the process so that nutrient absorption can occur. Any partially digested food left travels to the large intestine or colon and is considered waste product. As it travels the length of the large intestine towards the rectum, water is absorbed from the waste product.

Constipation is an issue that occurs in the large intestine, and it is caused by waste product traveling slower than normal due to sluggish muscles in the intestinal lining. The extra transit time allows for absorption of additional water, and this creates hard, dry stools. Certain medications and conditions, such as pregnancy, can cause intestinal muscles to contract slower and less forcefully and contribute to constipation.

However, three of the most common culprits that impact intestinal transit are lifestyle related. These are activity, fiber intake and hydration status, and adjusting daily habits that impact these is an easy way to decrease constipation frequency, as well as to potentially ease existing constipation that's mild to moderate. Here's why each lifestyle habit is so important and how to incorporate them.

1. Stay Active

Moving the body helps to physically move food through the intestines. Increased heart rate and blood flow also can help to stimulate intestinal muscles. Regular exercise is a good way to get activity, but you don't have to break a sweat every day to stay regular. It's sedentary behaviors that contribute to sluggish intestinal transit, so the goal is to be active. Some days this may consist of exercise, while other days it may consist of cleaning house, walking the dog or making a point to stand more than sit.

2. Get Plenty of Fiber

Fiber adds bulk to your waste product which stimulates contractions in the intestinal walls to keep things moving. Most people consume significantly less than the 25 to 38 grams per day that are recommended. To gauge your average daily intake, you could track your food intake for a few days using an app. Once you know your typical fiber intake, increase that amount by a few grams each week slowly working towards the recommendation. The key is to go slow and be sure to drink lots of water.

If you don't want to track, an easy place to start is to incorporate more vegetables and beans, choose whole grains over refines, and snack on fruit and nuts. Fiber supplements can be helpful to reach the recommendation, but don't rely solely on them to meet fiber needs. Too much of certain forms can actually contribute to constipation.

3. Stay Hydrated

Adequate daily water and fluid intake is essential for preventing constipation. Even mild dehydration can impact the body's water balance and digestive secretion which can lead to drier than normal waste product when it enters the large intestine. Coupling this with excessive water absorption due to sluggish transit can lead to bowel movements that are hard and dry and may even cause straining and pain. Aim to get a minimum of 64 fluid ounces of water or similar fluid per day, but you may find it easier to stay hydrated getting 80 or more fluid ounces. Also, make sure to consume adequate fluids when increasing your fiber intake.

These three lifestyle approaches can reduce frequency, but constipation may still occur, on occasion, when you have schedule change such as when traveling. Mild to moderate constipation may also be resolved for some with these approaches, but always see your doctor if constipation continues or if you experience severe pain, bleeding, or other unusual symptoms.

Carolyn Williams, PhD, RD, is author to the new cookbook, Meals That Heal: 100 Everyday Anti-Inflammatory Recipes in 30 Minutes or Less, and a culinary nutrition expert known for ability to simplify food and nutrition information. You can follow her on Instagram @realfoodreallife_rd or on carolynwilliamsrd.com.