Can Eating More Fiber Make Constipation Worse? Gastroenterologists Explain

It’s not a coincidence that countless people suffer from constipation and the majority of adults don’t get enough fibre in their diets. But can eating more fibre actually make constipation worse? While it seems like the answer should be no, it’s not quite that simple.

“Not getting enough fibre can contribute to constipation. Fibre helps increase stool bulk and, depending on the type of fibre, can help stool retain water and become easier to pass,” explains Dr Tawadros. “However, constipation is not always caused by inadequate fibre, and increasing fibre does not help everyone.”

Read on to discover how and for whom increasing your fibre intake can actually worsen constipation, plus how to incorporate more fibre into your diet in a healthy, gut-friendly way.

How can fiber make constipation worse?

There are a few ways that increasing your fibre intake can make you feel more backed up than when you started. Here are the biggest ones doctors say you should know.

You increased your intake too quickly

The first way more fibre can make constipation worse is if you increase the amount of fibre you’re eating too quickly, especially if you weren’t eating much to begin with. “A sudden increase in fibre can lead to bloating, gas and firmer stools before the digestive system has time to adapt, making constipation feel worse temporarily,” explains Dr Nahar.

You didn’t increase your fluids

If you quickly increase your fibre intake without upping your fluids at the same time, you may run into some problems. “Some types of fibre absorb and retain water, which helps produce softer, easier-to-pass stools. If fibre intake is substantially increased without adequate fluid intake, the stool can become bulkier without becoming sufficiently soft, potentially making it more difficult to pass,” Dr Tawadros says. He adds that if you start taking a fibre supplement like psyllium without drinking enough water along with it, you’ll likely experience this effect.

You have an underlying health condition

While everyday triggers like not eating enough fibre, not drinking enough water, lack of exercise and constantly changing routines can all contribute to constipation, there are also some health conditions that can cause constipation – and if you have one of them, upping your fibre likely isn’t going to help. “People with very slow movement of stool through the colon, faecal impaction, or difficulty evacuating stool due to pelvic floor or defecatory disorders may experience more bloating, pressure and discomfort when large amounts of fibre are added,” says Dr Tawadros. “Patients with a known or suspected intestinal narrowing, stricture or obstruction should also be cautious about substantially increasing bulky fibre and should discuss it with their healthcare provider.”

He adds that for people who have irritable bowel syndrome with constipation (IBS-C), increasing intake of soluble fibre (the type that dissolves in water) may improve constipation while insoluble fibre (the type that doesn’t) may cause bloating, discomfort and potentially make it worse.

You didn’t consider the type of fiber

Simply eating more fibre-rich foods without considering the type of fibre you’re consuming may not yield the results you’re looking for. “Not all fibre is the same,” says Dr Nahar. “Soluble fibre attracts water and then dissolves, while insoluble fibre adds bulk to the stool. Too much of one type can lead to digestive issues, especially if your body tolerates one type better than the other.”

Dr Tawadros adds that when it comes to constipation, soluble fibre, which is found in foods like psyllium, oats, beans and apples, tends to be the most helpful. Meanwhile, fermentable (or prebiotic) fibres, like those in bananas and cabbage, may cause gas and bloating, and some coarse insoluble fibres, like those in whole wheat flour, nuts and cauliflower, may worsen symptoms for people with sensitive gastrointestinal tracts.

Strategies for increasing your fiber intake

The good news is that if you increase your fibre intake the right way, chances are it will have the intended effect and improve your constipation. The key, say Dr Nahar and Dr Tawadros, is to do so gradually, over several weeks, incorporating different high-fibre foods into all of your meals throughout the day. “For most adults, a reasonable goal is approximately 20 to 30 grams of fibre per day, preferably from a variety of foods such as fruits, vegetables, whole grains, legumes, nuts and seeds,” Dr Tawadros says.

In addition, Dr Nahar stresses the importance of drinking plenty of water and staying physically active, both of which can help you avoid constipation and help your body adapt to a higher fibre intake. And if you need to take a fibre supplement to boost digestion, Dr Tawadros suggests psyllium husk. One study published in Food Bioscience found that psyllium husk helps relieve and reduce constipation and nourish the gut microbiome.

The bottom line

Adding more fibre-rich foods to your diet is an excellent way to combat constipation – but if you add too much too fast, don’t up your fluid intake to compensate, don’t vary your fibres, or have a health condition that’s making you backed up, this strategy can backfire. Increasing your fibre intake gradually with a wide variety of foods is the best way to improve constipation.

That said, if you’ve gradually increased your fibre intake and nothing has changed, it may be time to give your doctor a call. “If constipation persists despite these measures – or if it is accompanied by rectal bleeding, unexplained weight loss, significant or worsening abdominal pain, vomiting, anaemia, or other concerning symptoms – it should be evaluated by a healthcare professional,” says Dr Tawadros. They can help you get to the bottom of things and eliminate your constipation for good.

Dietary supplements are products intended to supplement the diet. They are not medicines and are not intended to treat, diagnose, mitigate, prevent or cure diseases. Be cautious about taking dietary supplements if you are pregnant or breastfeeding. Also, be careful about giving supplements to a child, unless recommended by their healthcare provider.