A Guide to Fibre

Fibre is an essential component of your daily diet – just as important as protein, fats and carbohydrates. But chances are, you’re not eating enough of it.

Adults need between 25 and 35 grams of dietary fibre every day, though most of us are lucky if we get 10 grams.

Fibre is an important nutrient for many reasons. It helps protect against heart disease and diabetes, can assist with weight loss, and – of course – it keeps you regular.

What is fibre?

Fibre is essentially a carbohydrate which can’t be digested by the human body. It’s found in plant foods, such as fruits, vegetables, whole grains, beans, nuts, and seeds. Unlike most nutrients, it’s not absorbed by your body, and passes through your digestive tract largely intact. Yet fibre is very important to good digestive health and also protects against several serious diseases.

There are three types of dietary fibre:

Soluble fibre dissolves in water, and turns into a type of gel during digestion. This slows the process of digestion and nutrient absorption.

Good sources of soluble fibre include:

  • Oat bran
  • Barley
  • Nuts and seeds
  • Legumes (dried peas, beans, lentils)
  • Apples, pears, and citrus fruits
  • Vegetables, such as potatoes and Brussels sprouts

Insoluble fibre doesn’t dissolve in water. Instead, it absorbs many times its weight in water. This creates a soft bulk and appears to speed up the passage of foods through your stomach and intestines. It also adds bulk to the stool.

Good sources of insoluble fibre include:

  • Wheat, corn and rice bran
  • Couscous
  • Brown rice
  • Whole grain cereals and breads
  • Dried beans and peas
  • Nuts and seeds

Resistant starch is the part of starchy foods (approximately 10%) which is tightly bound by fibre and resists normal digestion. Friendly bacteria in the large bowel ferment and change the resistant starch into short-chain fatty acids, which are important to bowel health and may protect against colon cancer.

Examples of starchy foods include:

  • Bread
  • Cereals
  • Rice (cooked and cooled)
  • Pasta
  • Potatoes (cooked and cooled)
  • Legumes

Fibre and weight control

Fibre can assist with weight control in several ways. Fibre-rich foods such as fruit, vegetables, potatoes, whole grain breads, and brown rice contain few calories per volume. Because they’re bulky, these foods keep you feeling fuller for longer. Similarly, you’re also inclined to eat less of high-fibre foods since they’re so filling. Even the extra chewing time can contribute to feelings of satiety.

On the other hand, low-fibre foods such as cakes and chips are more concentrated in calories and less filling. Therefore, you can easily overeat and consume excessive calories from low-fibre foods before your appetite is satisfied.

For example, compare an apple (high-fibre) and a glass of apple juice (low-fibre). Two or three apples are needed to produce one glass of apple juice. In the juicing process, all the fibre is removed and the sugar and calories become more concentrated. When you choose the apple juice instead of the apple, you consume far more calories and feel less satisfied.

Why is fibre important?

Including fibre in your diet leads to many health benefits.

Type 2 diabetes – A high-fibre diet seems to reduce your risk of type 2 diabetes. Foods which are high in fibre often have a low glycemic index ,and therefore help regulate blood sugar levels. Low-fibre foods, on the other hand, are generally high on the glycemic index and cause big spikes in blood sugar levels. A diet low in fibre and high in high glycemic index foods can more than double your risk of this disease.

Cancer – Do high-fibre diets reduce the risk of colon cancer? Research shows varying results. One of the most recent large-scale studies provides evidence in favour of fibre’s protective role against colon cancer, finding those eating a high-fibre diet (36g or more of daily fibre) were 25% less likely to develop polyps than those eating fewer than 12g of fibre daily.

Heart disease – If you have a high intake of dietary fibre, your risk for heart disease can be significantly reduced. In a Harvard study, those who had a high dietary-fibre intake had a 40% lower risk of heart disease than those with a low fibre intake. The fibre in whole grains appears to be particularly beneficial. Several studies also suggest higher fibre intake may help prevent metabolic syndrome (a combination of medical disorders including obesity, insulin resistance, high blood sugar, dyslipidemia and high blood pressure).

Digestive disorders – Since insoluble fibre speeds up the passage of foods through the stomach and intestines, it helps to prevent and alleviate constipation. The fibre contained in wheat bran and oat bran is particularly effective. Fibre may also help reduce your risk of diverticulosis, a disease involving inflammation of the bowel, which affects a large percentage of the western adult population. Increased fibre consumption can also help to alleviate the symptoms of this disease.

Good nutrition – Many high-fibre foods are also rich sources of vitamins, minerals, and antioxidants. If you’re eating enough fibre, you’ll inevitably also benefit from eating more of these nutrients.

How much fibre do I need?

The recommended daily intake of fibre is 25-35g per day for adults. The average Australian only eats less than 20g of fibre per day.

Desirable fibre intake for children (under 18) is calculated by age + 5g. For example, a six-year old needs 6 + 5g = 11g of fibre per day.

It’s possible to have too much fibre. Excess fibre can interfere with your absorption of minerals such as calcium, iron, magnesium and zinc, and upset nutritional balance. However, you’d need to eat excessive amounts of fibre for these problems to occur.

Combinations of foods that can provide you with enough fibre across the day include:

  • High-fibre breakfast cereal (5g) + 4 slices wholegrain bread (6g) + 3 servings fresh fruit (9g) + 35g raw almonds (5g)
  • 1 cup brown rice (4g) + 3 servings of vegetables (6g) + ½ cup corn, peas or lentils (5g) + 3 medium figs (5g) + 3 servings fresh fruit (9g)
  • 1 cup wholemeal pasta (8g) + 3 servings of vegetables (6g) + 1 cup bean soup (6g) + 3 servings fresh fruit (9g)
  • 1 cup porridge (2g) + ½ cup wholemeal pasta (4g) + 1/2 cup sunflower seed kernels (5g) + 3 servings of vegetables (6g) + 3 servings fresh fruit (9g) + 2 slices whole-grain bread (3g)

How to increase your fibre intake and avoid constipation

When increasing your fibre intake, do so slowly. Add just a few grams at a time to allow your intestinal tract to adjust. Abdominal cramps, gas, bloating, diarrhoea, or constipation may result if you increase your fibre intake too fast. You should also increase the amount of fluid you drink; drink at least two litres of water daily, as fibre absorbs water.

Other tips for increasing fibre intake:

  • Start your day with a bowl of high-fibre breakfast cereal. Add 1-2 tbsp of unprocessed bran and wheat germ for extra fibre, or try adding nuts, dried fruits and seeds.
  • Eat whole grain breads instead of those made with processed flour.
  • Don’t peel fruits and vegetables – most of the fibre content is in the skin!
  • Snack on fruits, nuts, and seeds.
  • Add bran (barley/wheat/rice) or psyllium husks to soups, casseroles, yoghurt, smoothies, dessert and biscuit recipes.
  • Exercise regularly to strengthen the abdominal muscles and stimulate the gut.
  • Read food labels to check for fibre content.
  • Add beans to soups, stews, and salads.
  • Drink plenty of fluids, as fibre absorbs water!
  • Eat bean- or lentil-based dishes in place of meat-based meals a couple of times a week.
  • Eat whole fruits instead of drinking fruit juice.
  • Snack on raw vegetables instead of chips, crackers, or chocolate bars.
  • Experiment with international dishes that use whole-grains and legumes as part of the main meal. For example, Dahl curries (lentils) and Tabouli salad (bulgur wheat).
  • Avoid regular use of laxatives, as they can overstimulate your intestinal muscles and may make normal bowel activity impossible.

Fibre counter

Food Fibre (g)
Breakfast cereals
Kellogg’s All-Bran, 45g 12
Kellogg’s Just Right, 45g 3.8
Sanitarium Weet-Bix, 30g 3.3
Sanitarium Cornflakes, 30g 1
Uncle Toby’s Fibre Plus, 45g 6.4
Freedom Foods Gluten/Wheat-Free Muesli 3
Kellogg’s Special K, 30g 1
White, 1 slice, 25g 0.6
Wholemeal, 1 slice, 30g 1.8
Multi-grain, 1 slice, 30g 1.4
Dark rye bread, 1 slice, 30g 2.4
Hyfibre White, 1 slice, 37g 2
Wonder White, 1 slice, 33g 1.2
Fruit loaf, 1 slice, 30g 1
Pasta and Rice
White rice, cooked, 1 cup 1.6
Brown rice, cooked, 1 cup 2.4
Pasta, cooked, 1 cup 1.5
Wholemeal pasta, cooked, 1 cup 8.3
Nuts and Seeds
Almonds, raw, 30g 2.7
Peanut butter, 1 tablespoon 2.2
Sunflower seeds, 30g 3.3
Psyllium husks, 1 tablespoon 4
Apple, large, with skin 4.7
Avocado, 1/2 medium 1.2
Banana, medium 3
Kiwi Fruit, medium 3.5
Orange, large 6
Dried apricots, 30g 2.7
Dried figs, 30g 4.4
Asparagus, 5 spears 1.5
Beans, green, 1 cup 3.6
Carrot, 1 medium 4.2
Cauliflower, 1 cup 4
Mushrooms, 100g 2.5
Potato, medium, with skin 5.3
Lentils, Beans, Soybean products
Tofu, firm, 125g 2.8
Lentils, cooked, 100g 4
Red kidney beans, canned, 1 cup 13
Baked beans, 1/2 cup 6

For more information and fibre counts, refer to Allan Borushek‘s Pocket Calorie, Fat, and Carbohydrate Counter or the Food.com.au Food Database.

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