Within two hours of eating, our digestive system breaks carbohydrates into small sugar molecules called glucose which are absorbed into our bloodstream (and can also be stored in muscles and the liver if required). If we eat too much carbohydrate-rich food at one time, a high BGL reading is likely to occur — this is hyperglycaemia.
Alternatively, for people prescribed with insulin or certain types of BGL lowering medications, eating too little carbohydrate-rich foods can cause BGLs to drop too low — this is called hypoglycaemia and can be life-threatening if not treated appropriately.
How much carbohydrates should I eat for good nutrition?
The amount of carbohydrate individuals require is influenced by factors like age, weight, physical activity, current blood glucose levels and blood glucose targets (National Diabetes Services Scheme, 2016). As a general guide, Diabetes Australia recommend 30 – 40g (2−3 exchanges) of carbohydrates for women and 45 – 60g (3−4 exchanges) of carbohydrates for men within main meals, and 15 – 30g (1−2 exchanges) of carbohydrates within snacks (Diabetes Australia, 2020). It is also important that consumption of carbohydrate-rich foods is spread evenly across the day to prevent hyperglycaemia. Read more here to learn about carbohydrate serves
Now let’s focus on carbohydrate quality.
Carbohydrates (found in foods like bread, fruit, vegetables, milk, and also foods high in added sugar) are not created equally. In fact, there are three different types of carbohydrates.
- Sugars: include the natural sugar in milk (lactose) and fruit (fructose), and added sugars found in ultra processed foods like sauces, muesli bars, lollies, soft drinks and ice cream. These carbohydrates break into blood glucose almost instantly, causing a quick rise in BGLs.
- Starches: include starchy vegetables like potatoes and corn, grains like oats, rice, wheat and barley, lentils and dried beans. These carbohydrates break slowly into glucose, causing a gradual rise in BGLs compared with a quick rise from sugars.
- Fibre: is found in wholemeal breads, wholegrain cereals, fruits and vegetables. Since fibre remains undigested, it slows the breakdown of sugars and starches into glucose and this prevents large spikes in BGL. Although fruit contains fructose, the high amount of fibre is why fruit is a great source of carbohydrates – read more about this in an upcoming blog!
I believe careful consideration of both carbohydrate quantity and quality is essential for achieving target blood glucose levels and maintaining overall good nutritional adequacy. Although we each require a unique quantity of carbohydrates, we can all strive to focus on eating good quality carbohydrates.
Tips for increasing optimal quality carbohydrates in our eating pattern
- Replace refined white bread, rice and pasta with the wholemeal variety because they contain more fibre.
- Increase the variety of good quality carbohydrates in your diet by cooking grains like quinoa, cous cous, barley and amaranth.
- Limit your intake of foods and drinks containing added sugar to reduce refined carbohydrates. Check the ingredients list on the back of packaged foods and remember sugars are ingredients that end in “ose” like sucrose and fructose. Other ingredients containing sugar include brown rice syrup, corn syrup, molasses, fruit juice concentrate, honey and agave.
- Opt for whole fruit instead of fruit juice since the fruit contains more fibre than fruit juice and this prevents larger spikes in BGL.
- Ensure your yoghurt contains no added sugar and opt for milk (cows or plant based) which is unsweetened to further reduce your intake of unnecessary sugar.
If you would like personalised advice, education and strategies to improve your carbohydrate quality and intake, please book an appointment
Co- authored by student dietitian, Charlotte Manning
Reviewed by dietitian, Rebecca Greco
Centers for Disease Control and Prevention. (2019). Carb Counting. Retrieved from https://www.cdc.gov/diabetes/m…
Diabetes Australia. (2020). What Should I Eat. Retrieved from https://www.diabetesaustralia.…
National Diabetes Services Scheme. (2016). Carbohydrate Counting and Diabetes. Australia: NDSS.
Nutrition Education Materials Online. (2019). Carbohydrate Counting. Australia: Queensland Government.