Is it possible to get too much of a good thing? As with most of everything, moderation of fibre is key. Eating too much it (> 70 g daily)—as is common with whole- or raw-food diets—can result in you making a beeline for the bathroom, as well as other uncomfortable side effects.

Fibre is vital for a healthy digestive system. It facilitates fermentation and gas formation, and helps improve the bulk and regularity of bowel movements. In addition, a high-fibre diet can help with the regulation of lipid and blood pressure levels, diabetes control, and weight maintenance.

Fibre requirements

The American Heart Association recommends fibre intake from a variety of foods. Total dietary fibre consumption should range from 25 to 30 g daily from food—not supplement—sources. More specifically, the Academy of Nutrition and Dietetics recommends 25 g of fibre per day for women and 38 g a day for men. Adults aged 50 years and older should consume less fibre, at 21 g per day for women and 28 g per day for men. Pregnant or lactating women should eat 28 g of fibre per day.

Types of fibre

Fibre exists in two forms: soluble and insoluble. Even though the body can’t absorb either form, they are both necessary. Soluble fibre breaks down in water and forms a gel that keeps feces soft while slowing digestion. Insoluble fibre does not break down, instead adding bulk to stool and decreasing transit times. The body needs both types of fibre, so most research simply focuses on total fibre intake.

Too much fibre

Symptoms of eating too much fibre can include bloating, gas, cramping, constipation, diarrhea, reduction in appetite, and early satiety.

One of the negative side effects of overconsumption of fibre includes the underabsorption of key micronutrients, since fibre binds with minerals, such calcium, iron, magnesium, and zinc. Furthermore, high-volume meals can make it difficult to keep up energy intake, resulting in weight loss or lack of weight/muscle gain. Lastly, intestinal obstruction can occur in the setting of copious fibre intake but limited fluid intake.

What to do

If you are consuming too much fibre in your diet, try the following:

• Stop eating products with added fibre, such as high-fibre cereal bars or high-fibre breads
• At mealtime, replace high-fibre foods, including grains, with lower-fibre alternatives
• Avoid foods that cause bloating, such as sugar-free gum and candy
• Choose cooked over raw veggies
• Increase fluid intake
• Exercise more

In one prospective, longitudinal case study involving 63 patients with idiopathic constipation, reduced fibre intake decreased constipation, bloating, and stomach pain, and increased the frequency of bowel movements.

Specifically, during a period of 6 months, 41 patients were on a no-fibre diet, 16 were on a reduced-fibre diet, and 6 continued on a high-fibre diet due to personal or religious factors. Participants who stopped their dietary fibre intake completely went from having 1 bowel movement every 3.75 days to having 1 per day. In those who reduced their fibre intake, bowel movement frequency went from 1 every 4.19 days to 1 every 1.9 days.

High-fibre foods

Here is a list of high-fibre foods with values rounded to the nearest 0.5 g:

Finally, remember that fibre is a really important part of the diet. If a person feels sick from eating too much fibre, then a low-fibre diet may be a good idea for some time, with limited amounts of fibre gradually re-introduced into the diet.

This story is contributed by Naveed Saleh and is a part of our Global Content Initiative, where we feature selected stories from our Global network which we believe would be most useful and informative to our doctor members.