Side Effects of Eating Too Much Fiber

Fiber, found in whole grains like oatmeal, is healthy but can cause stomach pain.
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If you eat a standard American diet, the chances that you eat too much fiber are slim. However, if you do overdo it on whole grains, fruits and vegetables and beans -- some typical foods high in fiber -- you might find yourself suffering the consequences. When your digestive system isn't used to fiber, an increased intake can lead to abdominal discomfort such as gas, bloating and stomach pain.

The average American consumes between 10 and 15 grams of fiber a day, significantly less than the 20 to 35 grams recommended daily, according to the National Institutes of Health. Eating enough fiber helps aid digestion, preventing constipation, as well as keeping you feeling full and therefore helping to control weight. Fiber-rich foods include whole-grain cereals, dried beans and peas, fruits and vegetables.


Physical Side Effects

The first indication that you've eaten too much fiber in a short period of time will come from your midsection. Symptoms include flatulence, bloating and abdominal cramps, but as your tummy gets used to the increase in fiber, the symptoms should subside. In rare cases, excessive consumption of fiber in people with difficulty chewing or intestinal mobility has caused intestinal obstruction.

Nutrient and Drug Interactions

Consuming too much fiber could interfere with the absorption of certain nutrients or pharmaceutical drugs. According to the Linus Pauling Institute, adding cereal fiber can decrease the body's absorption of zinc, iron, calcium and magnesium; however, this could be due to phytate in the cereal fiber and not caused by the actual fiber. Additionally, LPI recommends taking medications one to two hours before or after fiber supplements because certain types can interfere with the absorption of common drugs such as acetaminophen, penicillin and tetracyclines.


Minimizing Effects

To lessen the likelihood of stomach pain, gradually increase your fiber consumption over a period of a couple weeks. When you plan to eat a healthy serving of fiber, drink plenty of water along with it to help it move through your digestive system. Peeling fruits and vegetables can also reduce the amount of fiber you consume; however, eating these fiber-containing peels is beneficial for your health. To avoid drug interactions, avoid taking fiber supplements near the time you take your medication.


Is This an Emergency?

If you are experiencing serious medical symptoms, please see the National Library of Medicine’s list of signs you need emergency medical attention or call 911. If you think you may have COVID-19, use the CDC’s Coronavirus Self-Checker.