Dietary fibre is often taken for granted.
We assume we get enough of it as part of a healthy diet and ideally we should. But in reality, when it comes to fibre many of us fall way short of the mark, compromising our health and potentially leading to weight gain.
“It’s recommended that women consume at least 25g of fibre a day and men at least 30g a day, but there’s a whole lot of people who aren’t meeting those basic requirements,” says Melanie McGrice from the Dietitians Association of Australia and founder of Health Kick Nutrition.
It’s also common for weight loss diets to be low in fibre, which is a big mistake, says McGrice.
“A lot of the weight loss diets, particularly the low carbohydrate diets, put people on really low levels of kilojoules, which often decrease their fibre intake,” she says.
“But fibre is really, really important for sustainable weight loss. For starters, if you’re on a diet where you’re not meeting your fibre requirements then you’re likely to feel very hungry, in which case the diet is going to be unsustainable.”
Fibre should be thought of as an aid to weight loss, says McGrice, as well as a great benefit to your entire health.
What is dietary fibre?
For such an essential part of our diet there remains a lot of confusion about what dietary fibre is and how to get enough of it on a daily basis.
Dietary fibre encompasses all parts of plant matter that can’t be digested or absorbed. Unlike proteins, fats and carbohydrates, fibre travels through the stomach, intestines and colon remarkably intact. But it has an incredibly important role to play.
Insoluble fibre, found in things like wholegrains, nuts and many vegetables, assists the general movement of food through the digestive system, preventing toxic build-up.
Soluble fibre works differently, dissolving in water and helping to balance glucose levels and lower blood cholesterol. Examples of foods containing soluble fibre include citrus fruit, oats, apples, carrots, beans and barley.
Why we need more
Despite the fact that fibre isn’t of great nutritional value in itself, it’s vital in maintaining health and preventing disease in so many ways.
“If you aren’t consuming enough fibre you’re at much greater risk of conditions such as diverticular disease, haemorrhoids and bowel cancer,” McGrice says.
“Research also shows that higher intakes of fibre tend to decrease the risk of heart disease and some types of cancer.”
Fibre regulates digestion and promotes healthy bowel movements, softening your stool and making it easier to pass, reducing your chances of constipation and, in some cases, reducing symptoms of irritable bowel syndrome.
According to the Mayo Clinic in the US, increased soluble fibre in the diet can reduce blood pressure as well as inflammation, resulting in a protective effect on the heart. Increased insoluble fibre also appears to reduce your chances of developing type 2 diabetes by regulating the absorption of sugar.
The role of fibre in weight management should also not be understated, with plenty of flow-on health benefits, including a reduced chance of heart disease, obesity and diabetes.
Fibre and weight loss
Research shows that women who have a high fibre diet tend to have lower body weight.
“The reason for this is threefold,” McGrice says. “First, foods that have fibre in them are much more filling for their portion sizes. Second, the more fibre you eat in a meal the lower the glycaemic index of the meal. So the fibre will help to slow down the release of carbohydrates into the bloodstream, meaning you will feel fuller for longer.
“Third, foods that are high in fibre tend to be lower kilojoule foods like wholegrain breads and cereals, and fruits and vegetables.”
It stands to reason then that boosting your fibre intake can help your weight loss efforts.
“I often suggest to my clients to increase fibre in their diet and focus on the positives rather than the negatives of what they can’t have,” McGrice says. “Fibre is certainly a weight loss key.”
A Spanish study published in the British Journal of Nutrition found people who took soluble fibre for a 16-week period lost over four kilograms more than those who took a placebo, as well as improving overall cholesterol levels.
Impressive results were also achieved by the Pennsylvania State University in the US, but in a much smaller time frame – two days. In the study the female subjects ate the same weight of food on both days but ate high fibre foods on the second day, consuming 30 per cent fewer kilojoules. Satisfaction levels were the same on both days.
Up your intake
The highest levels of fibre are found in some of the healthiest foods on the planet. In fact, if you’re not getting enough fibre it’s highly likely you’re not eating a nutritionally balanced diet. Good choices of fibre-rich foods include wholegrains and wholegrain cereal products, fruits and vegetables, nuts and seeds and beans, peas and other legumes.
Contrastingly, refined foods – the bane of the Western world – tend to be very low in fibre. Refined grains and cereal products, including white bread and pasta, are very low in fibre due to the process of removing the outer bran coat of the grain.
Canned fruits and vegetables also tend to be low in fibre, as are most juices.
“Juices, even freshly squeezed juices, don’t have much fibre,” McGrice says. “Most of the fibre is taken out. You’re far better to eat the fruit and vegetables fresh rather than juiced.”
Breakfast should be a high fibre meal. Opt for a fibre-rich breakfast cereal or alternatively add a sprinkle of wheat bran. In Australia if a product says it’s high in fibre it should contain 5-8g of fibre per serve.
When cooking, use wholegrain flour, brown rice, whole-wheat pasta and wheat bran instead of the refined alternatives.
Fruits and vegetables should also be consumed in abundance, says McGrice.
“You might have a smaller portion of meat and larger servings of vegetables or you might have a piece of fruit instead of a chocolate bar,” she says.
“If you have five serves of vegetables, two serves of fruit plus four serves of wholegrain breads and cereals then you’ll get to 25g of fibre a day, which is what you should aim for.”