By Rob Hobson
Carbohydrates have a bad reputation, but they provide important health benefits and are a vital part of a balanced diet.
There's no doubt that nutrition has a huge role to play when it comes to health. The food choices we make, alongside other lifestyle factors such as exercise and stress management, can influence both our longevity and our years spent free of disease.
Carbohydrates have been vilified in recent years, with low-carb weight-loss diets such as the Atkins and Ketogenic Diet leading to the idea that 'carbs are bad'. But carbohydrates are a broad category, and it's the type, quality and quantity of carbs that are important.
What are carbohydrates?
Carbohydrates, along with fats and proteins, are macronutrients that are required in larger quantities than micronutrients (vitamins and minerals) to provide energy.
Carbohydrates are broken down into glucose, which the body uses as its preferred source of energy. Dietary guidance says that 50 per cent of the calories we consume should come from this macronutrient.
Carbohydrates can be divided into sugars (those added to food and those found naturally in foods such as fruits), starches (those found in bread, pasta, grains and potatoes) and fibre, which is the indigestible component of these foods.
Aside from pure table sugar, most carbohydrate foods also contain some protein and fat.
Do carbohydrates make us fat?
This is where the type of carbohydrate is important. The high consumption of added sugar and other refined carbs (white bread and pasta, cakes, pastries, and sweets) is likely to play some role in weight gain, but these sugars can't be compared to other carbs, such as complex carbohydrates like oats, quinoa, wholegrain bread and pasta, and fruit and vegetables.
Low carbohydrate diets have become popular but, while shifting the percentage of macronutrients in favour of fat and protein has been shown to be a useful strategy for weight loss, this is mostly a short-term solution.
Can anyone really say they will never again eat pasta or rice, let alone forgo the comfort of toast, for the rest of their life?
What this all boils down to is balance, which is the key to eating well in the long term and doesn't involve cutting out one or other of the food groups from the diet.
So, here are five reasons why you should include complex carbohydrates in your diet.
1. Carbohydrates can reduce the risk of heart disease and cancer
Wholegrains are rich in fibre, which has been shown to reduce the risk of heart disease and bowel cancer.1
The average intake of fibre among New Zealand adults is less than 20g a day. This falls short of the Ministry of Health recommended 25g (for women) and 30g (for men) a day. Cutting out carbohydrate foods will limit fibre intake even more.
Oats contain beta-glucans, a soluble fibre shown to help reduce cholesterol by preventing its absorption in the gut.
Research has shown that consuming 3g per day of beta-glucans can help to reduce cholesterol levels by up to 10 per cent (40g of oats contains 1.5g of beta-glucan).2
Wholegrains have also been shown to help reduce the risk of bowel (colorectal) cancer, according to the World Cancer Research Fund (WCRF). Their latest report on bowel cancer has shown that eating 90g of wholegrains a day reduces the risk of disease by 17 per cent.3
2. Carbohydrates can help to support gut health
Certain fibres in food act as prebiotics, which feed the 'friendly' bacteria of the microbiome. These bacteria break down the prebiotics by a process called fermentation, which produces short-chain fatty acids required for energy metabolism. These fatty acids may also reduce the risk of inflammatory diseases.4
Prebiotics include inulin, lignin, oligosaccharides, mucilage gums, non-starch polysaccharides (pectin and beta glucans) and resistant starches. Foods that act as prebiotics include bananas, chicory, artichokes, leeks, oats, almonds, cashews, lentils and chickpeas, among others.
These foods are not suitable for those suffering with irritable bowel syndrome (IBS) and their exclusion in the diet forms the basis for the low-FODMAP diet.5
3. Carbohydrates provide essential micronutrients
Many carbohydrate foods are a rich source of B vitamins, which help the body to break down food and convert it into energy. This group of vitamins also play a role in keeping the skin, eyes and nervous system healthy.
Wholegrain foods such as oats, barley and rye bread also contain magnesium, which plays a role in over 300 enzymatic reactions, as well as supporting muscle and nerve function, immunity and regulating blood pressure. Such foods also offer a useful source of other minerals including iron and zinc, which are important for vegans and those on a plant-based diet.
4. Carbohydrates are a cost-effective way to eat
Eating on a budget is a serious concern for many, and carbohydrates offer a cost-effective and convenient base for any meal. Brown rice, wholemeal couscous and pasta can be combined with proteins and vegetables to make a simple meal, while all varieties of wholemeal breads can be used to make sandwiches or served as an accompaniment to soups, stews and salads.
5. Carbs are king for athletic performance
If you're serious about sport, then you will understand the importance of carbohydrates. The body relies on carbohydrates as its main source of energy, and this macronutrient is stored as glycogen in muscle and the liver.
While some Instagram gym bunnies may promote low-carb diets, those in the know appreciate that to train optimally and perform well in competition, the body must have carbohydrates.
The appropriate consumption of carbohydrates, such as energy gels, during and after training and during competition, is essential to maintain and maximise energy levels to promote performance.
Maintain the balance
Good nutrition is a basic requirement to sustain life, and we know that all the nutrients found in food have a role to play in the body.
Excluding or rejigging macronutrients has become fashionable in the world of wellness, but there's no guarantee that doing so will benefit your health long-term, and it's more than likely unsustainable. Balance is key, and choosing foods in their most natural state is ultimately the best way to eat.
1Barber, T.M., et al. (2020). The Health Benefits of Dietary Fibre. Nutrients. 12(10)
2Othman, R.A., et al. (2011). Cholesterol-lowering effects of oat β-glucan. Nutrition Reviews. 69(6)
3World Cancer Research Fund/American Institute for Cancer Research (2018). Diet, Nutrition, Physical Activity and Caner: a Global Perspective. Continuous Update Project Expert Report.
4Rios-Covian, D., et al. (2016). Intestinal Short Chain Fatty Acids and their Link with Diet and Human Health. Frontiers in Microbiology. 7
5Gibson, P.R., et al. (2017). The evidence base for efficacy of the low FODMAP diet in irritable bowel syndrome: is it ready for prime time as a first-line therapy? Journal of Gastroenterology and Hepatology. 32
Rob Hobson is a registered nutritionist who runs two successful nutritional consultancies and has worked for the NHS.