3 Ways Your Weight and Your Poop Are Connected

The ingredients to a good morning often involve a strong cup of coffee, a healthy breakfast, maybe a workout and — let's be honest — a solid poop (pun intended). But while this regular ritual may be immediately forgotten post-flush, your bowel movement can tell you a lot about what's going on in your body, and it may even be a window into your weight.

Yep — though it may seem strange, it's a fact about poop that it can indicate things like a gut bacteria imbalance, insufficient fiber consumption and possibly even chronic inflammation.

Here, we'll break down how these issues might be tied to the number on the scale.

Your weight may be affected by the levels of specific bacteria in your gut that are present in your poop, according to a September 2017 study in the ​International Journal of Obesity​. After assigning 62 participants with overweight a high-fiber Nordic Diet or a grainless Danish diet, researchers analyzed two types of gut bacteria (Prevotella and Bacteroides) present in participants' stool.

Those who followed the Nordic diet — rich high-fiber foods like leafy greens, whole grains and fruit — lost about seven pounds more than participants who followed the Danish diet — high in lean meat and eggs — but with one caveat: Only those with a higher level of Prevotella than Bacteroides in their poop lost the weight. People who followed the Nordic diet but didn't show higher levels of Prevotella didn't lose much more weight than participants following the Danish diet.

To simplify: Researchers realized that participants with different levels of gut bacteria found in their stool had different reactions to the diet. That seems to be why some participants experienced weight loss on the Nordic diet, while others did not.

So, how can you learn more about your own gut bacteria? While there are at-home gut bacteria tests on the market, they may not provide the most reliable results, according to the American Gastroenterological Association. Getting a clear image of your gut microbiome and levels of bacteria requires several samples and analyses. For a better understanding of your personal levels of gut bacteria, it's best to consult a gastroenterologist.

Fiber is a nutrient that plays a role in digestive health and regular bowel movement, according to the U.S. National Library of Medicine. There are two different types of fiber (soluble and insoluble), both of which are important in promoting good health and digestion. Soluble fiber is found in oat bran, nuts and beans and is known for slowing digestion. On the other hand, insoluble fiber, found in wheat bran, vegetables and whole grains, adds bulk to your stool and seems to help food pass more quickly.

Not only does fiber help keep you regular in the bathroom, but it is a good weight-management tool, according to the Mayo Clinic. High-fiber foods help control blood sugar levels, and they tend to be more filling, which means you're likely to eat less of them. Fiber-dense foods also tend to be lower in calories than many others.

When it comes to weight and body fat, eating soluble fiber has been linked to a lower risk of belly fat, according to a February 2012 article published in​ Obesity​. When researchers increased participants' intake of soluble fiber by 10 grams, they saw a 3.6 percent decrease in visceral fat (the fat that surrounds the internal organs). For participants that were moderately active, this decrease was even higher and they even saw a decrease in subcutaneous fat (the fat you visibly see on your body).

While it's well known that obesity is associated with a higher risk of certain conditions like heart disease or diabetes, it also seems to be connected to abnormal bowel movements, according to a September 2019 analysis in ​Alimentary Pharmacology & Therapeutics​.

After analyzing more than 5,000 participants, researchers found that people with obesity were 60 percent more likely to experience chronic diarrhea, regardless of their diet or level of physical activity.

The reason why isn't totally clear, but the researchers suggest the culprit may be chronic low-grade inflammation, which has also been linked to such serious health issues as cancer, heart disease and diabetes, according to the Mayo Clinic.

However, Alex Lickerman, MD, a Chicago-based primary care physician, tells LIVESTRONG.com that there's no firm connection between inflammation and diarrhea. Instead, he thinks the answer lies in diet, and notes that it's difficult to truly control for diet in observational studies.

It's true that chronic, low-grade inflammation is often caused by eating unhealthy, processed foods. Foods high in processed sugars, like cereals, candy bars and other snack foods, can raise the risk of chronic inflammation in the body and may potentially affect digestion and weight, according to the Mayo Clinic.

​Read more:​ How Dr. Weil's Anti-Inflammatory Diet Works — and How to Get Started