Carbohydrates has been under the microscope for being a foe to a healthy eating lifestyle. Carbohydrates come from plants. They are the body’s major source of fuel. They consist of sugars, starch, dietary fibre and resistant starch.
Sugars provide a quick source of energy (fuel) and are either ‘free’ or ‘intact’. ‘Free sugars’ are sugars that have been added to food such as flavoured yoghurt and milks, ready-to-eat cereals and muesli bars, jams and or naturally found in honey, syrups and unsweetened fruit juices. ‘Intact sugars’ are those naturally found in plain milk and yoghurt, fruits and some vegetables.
Starch provides a slower release of energy to the body compared with sugars. They are found in grains and cereals such as oats, rice, bread, wheat, rye, barley, quinoa, in legumes such as peas, beans and lentils and in starchy vegetables such as corn, potato, sweet potato, taro and cassava.
Dietary Fibre consists of soluble and insoluble portions. Soluble fibre can dissolve in water to form a thick gel and hence in the gut, it helps to slow down the process of digestion and stabilise blood glucose levels through slow release into the blood stream consequently providing satiation (feeling of fullness). Soluble fibre is also able to bind fatty deposits in the small intestine where digestion takes place and prevent cholesterol from being absorbed by the body hence lowering LDL (unhealthy) cholesterol levels. Sources of soluble fibre are oats, dried lentils and beans, vegetables and fruits.
Insoluble fibre is the portion of fibre that is indigestible. They provide bulk to waste material in the large intestine assisting with a smooth process of defaecation (poo) and keeping the large intestine healthy reducing the risk of constipation, colon cancer, diverticular disease and haemorrhoids. Sources of insoluble fibre are whole grain breads and cereals, the edible skins of fruit and vegetables, nuts and seeds, raw lentils, kidney beans and chickpeas.
Resistant starch, as its name clearly states, is the portion of starch that resist digestion. Instead it travels to the large intestine where bacteria ferment it producing gasses that provide a protective effect to the large intestine keeping it healthy. Sources of resistant starch include pasta ‘al-dente’ (slightly undercooked), cooked and cooled potato, unripe bananas and bread and cereal products that contain ‘hi-maize’.
One of the most important aspects of carbohydrates is its glycaemic index value.
Glycaemic index (GI) is the measure of how carbohydrates in different foods affect blood glucose levels. Not all carbohydrate foods digest, get absorbed and metabolised at the same rate. Low GI carbohydrates provides a slower release of glucose in the blood stream thus causing a slower rise in blood glucose levels. Low GI carbohydrates also promotes satiation (feeling of fullness) and provides a constant source of fuel for the body.
Glycaemic load is based on the amount of carbohydrate is eaten.
Carbohydrates is not a foe if you consume good quality carbohydrates in the appropriate quantity for your individual needs. They are rich in vitamins, minerals, phytochemicals, and fibre. Research shows that high fibre, low glycaemic index and low glycaemic load diets have beneficial effects on glucose metabolism. Research has also clarified that whole grains, are protective against type 2 diabetes or can assist with managing blood glucose levels in individuals living with type 2 diabetes.
There is currently no reported evidence suggesting that intact sugars have any adverse effect on health. However, there is cause for concern that free sugars in the form of sugar-sweetened beverages increases overall calorie intake and is likely to reduce the intake of nutritionally adequate sources, leading to weight gain and an increased risk of dental caries or diseases.
It is important to consult an Accredited Practising Dietitian for individual requirements and recommendations to ensure you are eating good quality carbohydrates and are not exceeding the amount required by your body. Specialist APDs can also provide appropriate advise for individuals who's digestive tact react adversely to fermentable sugars.