Why Is Consuming Too Much Fiber Bad?

By its very nature, fiber leaves you with a satisfying sense of fullness, so usually you’ll limit yourself from taking in too much. However, it is possible to go overboard with fiber. Vegans, and even and non-vegans who eat a great deal of fruits and beans, can push the outer limits of fiber intake. The Institute of Medicine, a federally funded nonprofit that makes recommendations about intake of nutrients, has set no upper limit to the amount of fiber healthy individuals can consume because of its self-limiting properties. The main problems you could experience from consuming too much fiber include gastrointestinal upset and diarrhea. Serious overconsumption, however, can begin to affect how well you absorb nutrients.


Intestinal Discomfort

You could experience abdominal cramping, bloating or gas if you suddenly increase the amount of fiber you regularly consume. According to the Linus Pauling Institute, you can mitigate the discomfort or prevent these symptoms altogether by drinking more water and making a more gradual increase in fiber. Your body can adjust to new levels of fiber intake better that way. People with digestive issues or problems chewing can experience more serious intestinal blockage if they consume too much fiber in a sitting.


An overload of fiber in your diet can cause diarrhea and worsen irritable bowel syndrome. Typically, a form of fiber is used to treat these problems. Because fiber soaks up a lot of water, it generally bulks up your stools and smooths their passage out of your system. However, excessive fiber can speed this process up. Here again, you need to go slowly in fiber intake. Also, be sure to eat a variety of both soluble and insoluble fiber. Soluble fibers form a gel-like coating in your intestinal tract, which delays the emptying of your stomach. Insoluble fiber doesn’t dissolve in water and has an effect similar to laxatives. Sources of soluble fiber include oatmeal, lentils, apples, oat bran, beans and peas. Insoluble fiber sources include nuts, barley, bulgur, raisins and the skins of root vegetables.

Poor Nutrient Absorption

According to a physician nutrition specialist advising “USA Weekend,” once you start consuming more than 40 g to 50 g per day, fiber can interfere with the absorption of important vitamins and minerals, especially calcium, zinc, iron, phosphorus and magnesium that are eaten in the same meal. That is a concern for people, like vegetarians, who must turn to beans for their protein source. To get enough protein, they consume a great deal of fiber along with it.

Fiber Intake Recommendations

Healthy adult women need about 25 g of fiber daily, according to the Institute of Medicine. The Dietary Guidelines for Americans 2010 says most Americans don’t get this much and encourages nearly everyone to consume more fiber in their diets. Older adults have different fiber needs. After age 50, a woman's need for fiber decreases to 21 g.


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This article reflects the views of the writer and does not necessarily reflect the views of Jillian Michaels or JillianMichaels.com.