Can I Eat Too Much Fibre?

Have you ever been asked to change your daily fibre intake? You may have been asked to eat more fibre if you suffer from constipation. Or perhaps you have been asked to reduce your fibre intake to follow a specific diet, such as for irritable bowel syndrome (IBS). You may have also been asked to adjust your fibre intake if you have symptoms of a specific digestive condition, such as diverticular disease. Confused? Most Probably! ¹ 

Consuming the right amount of fibre in your diet can be challenging. It is important to consume fibre as part of our daily diet; however, if we have an excess, it can cause certain digestive problems. In this article, we will discuss the importance of dietary fibre, the role it plays in our digestion, as well as some of the problems you may encounter if you consume an excess of fibre in your diet. 

What is dietary fibre?

Dietary fibres are a complex group of substances from different plant foods. Fibres cannot be completely broken down by human digestive enzymes and so pass through into the colon. Foods that are high in fibre are good for our gastrointestinal system and have a beneficial effect on gut bacteria. Gut bacteria partially break down some fibres while others cannot be broken down and pass through the gastrointestinal system undigested. Fibre passes through the gastrointestinal tract into the colon and forms the bulk of the faeces, helping in the peristalsis required for the faeces to move through the rectus.^2,5,6 Studies have shown that people who consume high fibre diets are less prone to certain health conditions such as cardiac disease, type 2 diabetes and bowel cancer.¹

Classification of fibre

According to the latest research, different types of dietary fibre can be categorised based on its physical characteristics, including:

• Solubility (dissolving ability)
• Viscosity (thickness)
• Fermentability (how it breaks down)

Soluble fibre: This type of fibre dissolves in water in our gastrointestinal tract and forms soft gel-like substances. The gut bacteria further breaks down the gel-like substance to form gases such as methane, hydrogen and short chain fatty acid (SCFA). SCFA is essential for our gastric health. Soluble fibre also acts as a prebiotic and helps grow good bacteria inside the bowel. However, excess soluble fibre can cause loose stools.⁵

Soluble fibre helps in reducing blood glucose and cholesterol levels. Foods with soluble fibre include fruits, oatmeal, nuts, lentils, beans and seeds. 

Insoluble fibre: Insoluble fibre absorbs high amounts of water and does not get dissolved in our gastrointestinal system. As it does not dissolve, it is more challenging for the gut bacteria to break down. As a result, insoluble fibre passes through the digestive system intact, simultaneously helping to move the food and waste products in our digestive system faster. Therefore, insoluble fibre is also called nature’s broom. Sources rich in insoluble fibre include whole wheat, wheat bran and nuts.⁵

Daily recommendations for fibre intake

For adults: According to government guidelines published in July 2015, a healthy diet should include 30 grams of fibre a day. It is estimated that most adults are consuming around 18 grams of fibre per day, and need to find more ways of adding fibre to their diet.³

For children: Children below 16 don't need as much fibre as adults. Children of 2 to 5 years need about 15 grams of fibre daily, 5 to 11-year-olds need 20 grams, and 11 to 16-year-olds need 25 grams. On average, teenagers and children consume only 15 grams of fibre daily. Encouraging a healthy diet with plenty of fruits and vegetables will help ensure that young people get adequate fibre in their diet.³

Benefits of fibre to our body

Substantial evidence suggests that eating plenty of fibre helps lower the risk of heart diseases, type 2 diabetes, stroke and bowel cancer. High fibre food takes longer to chew, which sends signals to the brain indicating fullness; this helps to prevent overeating. It also slows digestion and gives a feeling of fullness. .⁴

Research related to high fibre intake and gastrointestinal health has been going on since the 1970s, and it has various proven results of how fibre helps maintain a healthy gastrointestinal system.⁴ In patients with IBS, a high-fibre diet can help manage some common symptoms.

High-fibre foods

To increase your fibre intake you can include the following food items in your daily meal:

• Choose a breakfast with high fibre content. For example, whole wheat cereals (like Weetabix), whole wheat, multigrain bread, porridge, etc.³

• Replace some common carbohydrates with a higher fibre alternative. For example, choose brown rice, quinoa or bulgur wheat instead of white rice, or wholewheat pasta instead of white pasta.³

• Include more beans in your diet such as kidney beans, chickpeas, soybeans. You can try adding them to salads, curries or rice.

• Eat plenty of fruits and vegetables on a daily basis. If you are on a high protein diet with a high daily intake of meat, make sure you add vegetables as a side or as a salad. This will help to avoid constipation.

• Choose a healthy snack with a high fibre content, such as fresh fruit, oat cakes, vegetable sticks, unsalted nuts or seeds.

What is a balanced, high-fibre meal plan?

A balanced diet should consist of protein, carbohydrates, fat, fibre as well as all the vitamins and minerals that our body needs. Our body needs everything in proportion to stay healthy. Anything in excess/deficiency can cause some problems and having a balance is key. As mentioned above, the daily required intake of fibre is 30 grams per day, so while planning a meal we should take this into consideration. 

Are you consuming too much fibre?

As discussed above, different types of fibre have different actions on our digestive system. A balance of both types of fibre should be included in your diet. People with digestive problems can have a tricky relationship with dietary fibre.⁴

Symptoms of excess fibre: While fibre helps to relieve constipation, certain high fibre diets can cause constipation, bloating, gas production, cramps and even diarrhoea. Dietary fibres have different levels of solubility and fermentability. Though fermentation is good for gut health, it can cause gastric discomforts.⁴ Resistant starch is found in fibre-rich food like potatoes, bananas, pulses, seeds and wholegrain. This starch is not digested but rather it is fermented inside our large bowel by gut bacteria, producing gas and SCFA. It acts in a similar way to soluble fibre; however, it can contribute to the symptoms of bloating and wind.⁵

Consequences: High dietary fibre intake as such doesn't have any major consequences that can't be reverted. Certain high fibres can cause bloating, gas, cramps and digestion problems. However, if we reduce the fibre intake and drink a good amount of water, all the symptoms would subside. A high fibre diet has more pros than cons, hence it's always recommended by medical professionals to consume a high fibre diet.

What to eat if you are getting too much fibre?

If you feel discomfort because of a sudden dietary change to a high fibre diet, it's advised to take a break and start with less quantity and increase it gradually. When on a high fibre diet make sure to consume a good amount of fluids throughout the day. If you are taking artificial supplements for fibre stop it till symptoms subside and consult a dietician or a physician if your problems persist. Make a proper diet plan and note down the fibre content of your daily diet, this will help you to avoid over-consumption of fibre.

How to counteract the effects of excess fibre?

If a certain very high fibre diet is causing symptoms like constipation, diarrhoea, bloating, cramps and flatulence, try to increase your fluid intake which should help to ameliorate the acute symptoms. If you are taking fibre in the form of supplements you should stop that and eat natural foods such as fruits, vegetables, beans and lentils. Do some form of exercise regularly (that can include a walk in park) to help with peristalsis and bowel movements. If you feel you are having excess of fibre and experiencing discomfort, always consult a health physician or dietician who will help you in regulating a healthy balanced diet.⁷

Precautions with excess fibre

In any dietary fibre guidelines, the recommendation is to start with a small amount and slowly increase your intake. A sudden change of diet can cause adaptation problems for our bodies. One must consult a dietician or health physician for guidance if confused. It's always advisable to take fibre in its natural form, which means consuming more fruits, vegetables, grains, seeds and lentils. If taking artificial fibre supplements, never take more than the required quantity mentioned on the label. When you are on a high-fibre diet, make sure you drink a good amount of fluids regularly. Do some exercise and stay active.⁷

Summary

Dietary fibre is a double-edged sword for people with digestive problems. Whilst fibre can help with constipation, bloating and bowel movements, an excess can also cause the same problems. The key is to maintain a balance of different types of fibre, carbohydrates, protein, fats, fluids and other micronutrients required by our body. Anything in excess can cause various digestive problems. 

Studies have shown that people who eat a high fibre diet are less prone to heart diseases, type 2 diabetes and bowel cancer. It is also suggested that a high-fibre diet helps to control blood pressure, lower cholesterol and improve weight loss. Moreover, people who eat more fibre-rich foods tend to live longer than those who consume a low-fibre diet. Overall, a high fibre diet contributes to a healthy and longer life.¹