What Happens to Your Body When You Eat Too Much Fiber

Most Americans could benefit from eating more fiber, but more isn’t necessarily better.

Fiber is a nutrient that's important for health. It helps regulate digestion, manage cholesterol and stabilize blood sugars, according to the Centers for Disease Control and Prevention. But it is possible to have too much of a good thing. We'll talk about what fiber is, recommendations for fiber intake, what happens if you eat too much fiber, and what to do if you overdo it.

What Is Fiber?

Fiber is a type of carbohydrate that the body doesn't digest or absorb. Fiber is found exclusively in plant foods such as fruits, vegetables, nuts, seeds and whole grains.

There are two types of fiber: soluble and insoluble. Soluble fiber, when mixed with liquid, forms a gel-like substance that's important for good digestive health. It also helps reduce LDL cholesterol levels—the "bad" type of cholesterol, according to the CDC. Soluble fiber binds to this cholesterol and helps ferry it out of the body, notes the National Lipid Association. Some sources of soluble fiber are bananas, apples, oats, berries and avocados.

Insoluble fiber, on the other hand, does not attract liquids. It helps manage constipation by adding bulk to the stool and moving things along. It also promotes insulin sensitivity, says the CDC. Some sources of insoluble fiber are nuts, seeds, corn, whole-wheat flour and the skins of many fruits and vegetables.

Eating enough fiber is very important for health. The benefits of eating enough fiber include:

  • Managing cholesterol levels
  • Preventing heart disease
  • Stabilizing blood sugars
  • Promoting digestive health
  • Treating or preventing constipation
  • Promoting satiety
an illustration of a stomach with high fiber foods
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What Happens When You Eat Too Much Fiber

The CDC recommends eating 22 to 34 grams of fiber per day, depending on age and sex. "Everyone's tolerance to fiber will vary, so even the recommended daily amount may be too much if you haven't regularly been including fiber-rich foods in your diet," says Samina Qureshi, RDN, founder of Wholesome Start in Houston, a virtual nutrition practice that specializes in digestive health.

If you eat far more than the recommended levels or increase your fiber intake too suddenly, the following could occur.

You May Experience Gas and Bloating

According to the 2020-2025 Dietary Guidelines for Americans, over 90% of Americans do not consume enough fiber. However, if you increase your fiber intake too quickly, it can cause uncomfortable gastrointestinal effects, including gas and bloating. If you're trying to increase your fiber intake, do so slowly. You can try adding a few grams of fiber per week.

You May Not Consume Enough Calories

Fiber helps add volume to meals, which can help promote satiety. However, foods that contain fiber, such as vegetables, fruits, beans and lentils, also tend to be lower in calories. If you rely too heavily on fiber, you may end up feeling too full to eat other foods. "If you eat too much fiber without leaving room for other macronutrients, it can interfere with your ability to meet all your nutritional needs (fat, protein and micronutrients)," Qureshi says.

While many people worry about overeating, undereating has real consequences, especially when chronic. Ultimately, eating well-rounded meals that contain a balance of carbohydrates, protein, fat and fiber will help you feel your best.

You May Become Constipated

Overdoing fiber could lead to constipation for a variety of reasons. "Oftentimes people will hear that they need to eat more fiber if they are constipated, but it needs to be done in a slow and steady way while also increasing your hydration to avoid making constipation worse," Qureshi says. Because fiber absorbs water from the intestines, you should also make sure you're staying hydrated by drinking an adequate amount of water.

You May Develop a Bowel Obstruction

This is rare, but some people may develop a blockage in their intestinal tract, called a phytobezoar, if they consume too much fiber, a 2022 study in Nutrients points out. This happens when fiber builds up in the intestine and forms a ball that blocks things from passing through. Elderly people or those with certain digestive diseases may be at higher risk due to reduced digestive efficiency and reduced elasticity of the intestinal wall. Inadequate chewing could also contribute.

How to Relieve the Symptoms of Too Much Fiber

Symptoms of consuming too much fiber can range from mild to severe. If your symptoms are mild to moderate, here are some ways to help relieve them:

  • Drink fluids: This can help your digestive tract move things along and prevent dehydration from the high fiber intake.
  • Limit your fiber intake. Until your symptoms subside, lean on low-fiber foods to prevent exacerbating symptoms and allow your body time to digest the fiber you ate.
  • Do some gentle movement: Physical activity can help with bloating and constipation. If you're up for it, consider going for a leisurely walk or doing some gentle stretches.
  • Avoid carbonated beverages or gum: These foods can add air to the gastrointestinal system, which could lead to further bloating and abdominal discomfort.

When to See a Doctor

If you consume too much fiber, there's a rare chance a bowel blockage could occur. If you experience symptoms such as nausea, vomiting, fever, severe abdominal pain or an inability to pass gas or stool, see a doctor immediately.

How Much Fiber Should You Eat Daily?

Daily fiber recommendations vary based on your age and sex. The recommendations for daily fiber intake, according to the Dietary Guidelines, are:

Sex Age Fiber
Males and females 2-3 14 grams
Females 4-8 17 grams
Males 4-8 20 grams
Females 9-13 22 grams
Males 9-13 25 grams
Females 14-18 25 grams
Males 14-18 31 grams
Females 19-30 28 grams
Males 19-30 34 grams
Females 31-50 25 grams
Males 31-50 31 grams
Females 51+ 22 grams
Males 51+ 28 grams

If you have certain health problems, you may have different fiber needs. For example, if you have a digestive disease like irritable bowel syndrome (IBS) or inflammatory bowel disease (IBD), you may need a lower-fiber diet to mitigate digestive symptoms, or you may need to be especially careful about upping your fiber intake slowly. A registered dietitian can help you determine how much fiber you should eat and what foods are best for you.

Frequently Asked Questions

1. What should you do if you eat too much fiber?

If you ate too much fiber and are experiencing gas and bloating, limit your fiber intake until symptoms subside, drink plenty of fluids and try doing some light physical activity. You may also want to stay away from carbonated beverages or gum, as these can exacerbate bloating.

2. How much is too much fiber per day?

Currently, there isn't a maximum daily recommended intake for fiber, so be cautious about greatly exceeding the recommendations for your sex and age group. Also, be mindful of how your body responds to a high fiber intake.

3. What are the symptoms of eating too much fiber?

The most common symptoms of eating too much fiber are bloating, gas and abdominal discomfort. If you experience nausea, vomiting, fever or can't pass gas or stool, seek medical attention immediately.

4. Is it dangerous to eat too much fiber?

Most of the time, having too much fiber causes temporary discomfort without serious harm. However, in rare cases, too much fiber can lead to a blockage in the intestine that requires medical attention.

The Bottom Line

Fiber is important for your health, including helping keep your digestion regular and reducing your risk of diabetes and cardiovascular disease. However, it's possible to overdo it. Most people are not meeting the recommended amount of fiber. If you're looking to increase your fiber intake, do so slowly to prevent gastrointestinal distress. And remember, it's all about balance. While fiber is important, don't neglect protein, fat and other carbohydrates.

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