Carbohydrates

Carbohydrates are the main and preferred source of energy for our body. Carbohydrates are digested and broken down into glucose, which fuels bodily functions and physical activity, making them an essential part of our diet.

Types of Carbohydrates
Not all carbohydrates are created equal. Carbohydrates can be classified based on their chemical structure and the speed required for the body to break down and absorb them. There are 3 types of carbohydrates: simple carbohydrates (sugars), complex carbohydrates (starches) and dietary fibre.

  1. Simple Carbohydrates or Sugars
    Simple carbohydrates are quickly digested into glucose and absorbed into the blood stream, causing your blood glucose level to rise rapidly. The sudden rise in blood glucose level may give you a short burst of energy, only to be followed by sluggishness when the blood glucose level dips.
    • Naturally occurring sugars can be found in foods like fruit, milk and dairy products. These foods are nutrient-dense; they contain vitamins, minerals, fibre and phytochemicals that are necessary for good health.
    • Added sugars refer to refined sugars and syrups added to food and drinks during processing, preparation, or at the table. Added sugars contribute to intake of ‘empty’ calories, meaning it provides mainly energy but minimal amount of other nutrients such as fibre, vitamins and minerals. Excessive intake of simple sugars can lead to weight gain and obesity, thus increasing the risk of chronic diseases.
  2. Complex Carbohydrates or Starches
    Complex carbohydrates or starches are digested and broken down into glucose at a slower rate, leading to a gentler rise in blood glucose level and providing a steady release of energy.
    • Whole-grains are unrefined grains that contain the bran, germ and endosperm, making it a more nutritious option. Whole-grains are good sources of fibre that increases satiety, boosts digestive health and lowers the risk of heart disease. They also contain B vitamins, vitamin E, magnesium, potassium and selenium that promote good health and may protect against some cancers.
    • Refined grains have been milled to remove the bran and germ to leave behind only the endosperm, hence are lower in fibre and other nutrients. Refined grains include white rice, white pasta, white bread and products made from white flour such as biscuits and pastries. These foods tend to be higher in GI (glycaemic index), which means that they cause a more rapid rise in blood sugar levels after consumption.
  3. Dietary Fibre
    Dietary fibre is the indigestible portion of plants foods that cannot be broken down or absorbed by the body. Unlike sugars and starches, it cannot be digested into glucose for energy. Research has also shown the many benefits of fibre on digestive health, weight management, blood glucose control, lowering risks of heart diseases and cancers. There are two types of fibre:

    • Soluble fibre dissolves in water to form a gel-like material. It can be found in oats, peas, beans, apples, citrus fruits, carrots, barley and psyllium.
    • Insoluble fibre provides roughage to bulk up stools and promote bowel movements. Whole-wheat flour, wheat bran, nuts, beans and vegetables, such as cauliflower, green beans and potatoes, are good sources of insoluble fibre.

    What is Glycaemic Index (GI)?
    The glycaemic index is the ranking of carbohydrate-containing foods based on how quickly and how much they raise blood glucose after digestion and absorption. The foods are ranked from a scale of 1 to 100.


    Image from Temasek Polytechnic

    GI is Not the Only Factor to Choosing Foods
    GI does not reflect the amount of nutrients in the food. For example, the GI of fruits can be higher than that of chocolate. This does not mean that we should replace fruits that are rich in important nutrients with chocolate. GI can also be affected by other factors such as the presence of other nutrients (e.g. side dishes containing protein, fat and fibre), ripeness of the foods, quantity of the food consumed; and cooking and processing methods.

    What is Glycaemic Load (GL)?
    The effect of a carbohydrate food on blood glucose levels is not only determined by its quality (GI) but also by the quantity of carbohydrate in a food. Glycaemic Load (GL) is a measure that combines the overall effect of both quality and quantity of carbohydrates. GL is calculated with the following formula:
    Glycaemic Load = GI x Carbohydrate (g) content per portion ÷ 100.

    • Low Glycaemic load (low GL): 0 to 10
    • Medium Glycaemic load (medium GL): 11 to 19
    • High Glycaemic load (high GL): 20 and over

    GL may be useful for individuals with diabetes to assess the appropriate quantity of food required to maintain their blood glucose levels within the ideal range.

    Balance is Key
    Following the principles of low-glycaemic index eating is likely to be beneficial for individual with diabetes.

    However, consuming a healthy balanced diet and staying at a healthy weight is also important for your blood sugar and your overall health.

    Learn more about healthy eating with SHF’s Heart Smart Eating Guide.

    Tips for Healthier Carbohydrates

    • Select unprocessed or minimally processed carbohydrates such as whole-grains, vegetables, fruits and legumes that not only provide energy but are also rich in fibre, vitamins, minerals and phytochemicals.
    • Limit foods and drinks that are high in simple sugars and provide calories but have little nutrients.
    • Be mindful of how the carbohydrates are prepared, go for lower fat and lower salt cooking. For example, choose plain brown rice instead of fried or flavoured rice, choose baked potato over French fries.
    • Use the Heart Smart Eating Plate as a guide for portion control.
    • Consume whole fruits instead of fruit juices.
    • Go for unsweetened dairy products such as plain milk and unsweetened yoghurt.

    Disclaimer: The content on this page is for information only, it is not meant to substitute direct medical advice from your doctor or clinician.

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