There is a lot of attention focused on carbohydrates, and whether or not they are good for our bodies. The human body is able to utilise energy from four dietary sources: protein, fat, alcohol and carbohydrate.1 Of these, carbohydrates are the body’s preferred energy source, and critical for the brain and central nervous system to function.1
Foods that contain carbohydrate include:
When we eat carbohydrate-containing foods, our digestive system breaks them down into glucose.2 Our pancreas then releases the hormone insulin, which facilitates the movement of glucose into our bloodstream, increasing our blood glucose levels.2 The glucose is then able to travel around the body supplying energy. The rate at which carbohydrate enters our blood stream and causes a rise in our blood glucose levels is known as the glycaemic effect.2 The glycaemic index ranks foods based on their effect on blood sugar levels, as either high glycemic index (high GI) or low glycaemic index (low GI).2
Figure 1 compares the change to our blood glucose levels after we eat high GI versus low GI foods. As you can see, high GI foods cause a sharp and quick increase in blood glucose levels, followed by a steep decrease.2 It is this steep decrease that is associated with feeling hungry again soon after eating, and craving sugary foods, as our body tries to keep blood glucose levels stable.2 Conversely low GI carbohydrates elicit a steadier glycaemic response, including a slower decline.2 So based on this, which types of carbohydrate food should we be choosing?
Ideally you should aim for majority of your carbohydrate intake to be low GI choices. It is not about perfection – we like to use the 80/20 rule! Eighty percent of the time try to choose low GI carbohydrates and then the other twenty percent of the time applies to special occasions or occasional treats. A general rule of thumb with carbohydrates is the more grains the better! Table 1 lists some common high GI and low GI choices.
Table 1: Common high GI and low GI carbohydrate-containing foods.2
Now that we know which carbohydrate-containing foods are the best, the portion sizes are equally as important. The recommended standard serve of common carbohydrate-containing foods are3:
Carbohydrate containing foods also have many other health benefits.4 For example, wholegrain breads and cereals are an excellent source of dietary fibre, which is critical to our bowel health.4 Furthermore, they also contain B-vitamins, folate, iodine and iron.4 Due to this carbohydrate-containing foods are a core component of our diets.
Everyone is a little bit different in terms of how many serves of carbohydrate they need. Some people require 5-6 serves a day, others may be more or less. The type and amount of carbohydrates you choose is particularly important if you have diabetes. We recommend a one-on-one consultation with one of our dietitians to receive personalised dietary advice regarding carbohydrate intake for you.