Can You Eat Too Much Fiber? An RD's Answer About This Vital Nutrient

Fiber is a crucial component of a healthy diet, but too much of anything can lead to unwanted consequences. I rarely get asked, “Can I eat too much fiber?” But when I do, the answer is, “Yes!”

The amount of fiber considered too much can vary based on an individual's age, sex, and overall health. However, a general guideline is to aim for 14 grams of fiber for every 1,000 calories consumed per day.

According to the Institute of Medicine (IOM), the recommended daily fiber intake is as follows:

• For men: 38 grams/day (ages 19-50) and 30 grams/day (ages 51 and older)

• For women: 25 grams/day (ages 19-50) and 21 grams/day (ages 51 and older)

There are plenty of people who don’t eat enough fiber and they need to increase it. I see clients who determine they are going to “eat healthier” and start pounding down fruits and vegetable. It is a dramatic change for the body, and it is important to note that a sudden increase in fiber intake can cause digestive discomfort, such as bloating, gas, and cramping. To prevent these symptoms, it is recommended to increase fiber intake gradually over a period of several weeks (see this article for more information how to add fiber and limit unwanted digestive distress).

The digestive system is only designed to process a certain amount of fiber, and when we consume more than the recommended amount of fiber, it can cause bloating, abdominal pain, constipation, and even diarrhea. This is because fiber absorbs water in the gut, which can cause the stool to become too bulky and difficult to pass.

TOO MUCH FIBER ALSO IMPACTS YOUR LONG-TERM HEALTH

Additionally, consuming too much fiber can also interfere with the absorption of essential minerals and vitamins, such as calcium, iron, and zinc. This can lead to nutrient deficiencies, which can have serious consequences for your health. I talk about the massive impacts nutrient insufficiencies and deficiencies have on long-term health often because most of the people I work with have at least one, if not more, unrecognized deficiencies for years by the time they start working with me.

MANY OF THE CLIENTS I WORK WITH COME TO ME COMPLAINING OF:

• Abdominal pain

• Excessive and uncomfortable bloating

• Burping

• Constipation and/or diarrhea

• Gas

They often tell me that they believe they have a bacterial imbalance, parasitic infection or SIBO, because that is what they have seen online. They haven’t even considered the amount of fiber they are consuming. Because they don’t feel, they just start trying to eat MORE fruits and vegetables. While their symptoms can most certainly be due to those issues, the reality is that most often the solution to someone’s health issues is more simple than what your current favorite influencer is telling you. Why? Because so many women are getting terrible advice about what to eat. And I see a fair share of healthy “advice” floating around the Internet that actually includes an excess of fiber.

Instead being told to eat more OPTIMAL CALORIES and PROTEIN to meet current health goals, women are told to do extreme things, like eat 10+ fruits and vegetables daily - despite research studies finding limited additional health benefits past eating 5 fruits and vegetables daily. (It’s a little shocking to read in today’s wellness culture of MORE is better, but this latest study yet again found the same result). As always, if the recommendation changed, we would change the recommendation, but there is just not enough evidence for me to suggest recommending a higher intake. Plus, based on antidotal evidence as a practitioner who has helped thousands of people include optimal fiber, fruits, and vegetables into their diet, more does not go better for digestion, bloating, and gas from my experience and, in fact, simply hitting optimal fiber recommendations without rocketing beyond it resolves many digestive woes.

MORE FIBER IS NOT ALWAYS BETTER

There are plenty of clients that I do need to encourage to eat more fiber, but it's important to note that while fiber is an important part of a healthy diet, you don't need to eat more than the recommended grams of fiber for your age and sex unless you have specifically been told by a reputable health practitioner to eat more based on your unique health situation to receive its benefits. Note: a reputable health practitioner means that they have years of experience treating gut issues that actually resolve or are managed appropriately. A standard “nutritionist” (no license, just a random online education taking online exams) without gut health expertise or a general GP (who gets a miniscule amount of education on nutrition) would not be considered an authority you should listen to in this situation and a second opinion is needed. Standard, cookie cutter recommendations will be what they tell you and these do not immediately work for the average person that has had digestive woes that go unresolved for months or years.

YES, YOU CAN EAT TOO MUCH FIBER

It's best to focus on eating a variety of fiber-rich foods, such as whole grains, fruits, vegetables, legumes, and nuts in recommended amounts. This will help you get all the fiber you need, while avoiding the unwanted symptoms that can come from consuming too much of one food category.

Yes, you can eat too much fiber! So see a Registered Dietitian if you suspect you’re eating too much fiber and limiting your intake hasn’t helped to improve your symptoms. Your gut will thank you!

Sources:

• Institute of Medicine (IOM). (2005). Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids. National Academies Press. Circulation, March 14, 2021.