So now that you have a basic idea of what macronutrients are and what they do, let’s start looking at each one in a little more detail. We will start with carbohydrate.
As you know, carbohydrate provides us with energy. But there are some foods that are better sources of carbohydrates than others, and this is what we are going to look at in this article. Carbohydrates used to be classified as either ‘simple’ or ‘complex, but are now given a numerical rating knows as their glycemix index. Glycemic Index, or GI, is a way to rate carbohydrate containing foods and drinks according to how quickly they are absorbed and raise the blood glucose level of the blood.
Foods that contain carbohydrates include bread, breakfast cereals, rice, pasta, legumes, corn, potato, fruit, milk, yoghurt, sugar, biscuits, cakes and lollies.
GI can be used to help you choose better carbohydrate sources to fuel your body. Foods with a low GI will give you longer lasting energy than those with a higher GI.
One important thing to note is that food is not automatically a good source of fuel if it has a low GI. If fat or protein or even a food with a lower GI is combined with high GI foods, it will average the GI, brining it down. For example, Nutella is actually a low GI food, because of the amount of fat added to it. Similarly, a piece of white bread with butter will have a low GI overall, but this doesn’t make it a good source of energy for our body!
Here are some examples of low, medium and high GI foods:
- Low GI (less than 55) – soy products, beans, fruit, milk, pasta, grainy bread, porridge and lentils.
- Medium GI (55 to 70) – orange juice, basmati rice and wholemeal bread.
- High GI (greater than 70) – potatoes, white bread and long-grain rice (other than basmati).
Glycemic index is a
very useful tool in guiding us to choose good sources of carbohydrate, as long as we are aware of the limitations. Some fruits, vegetables and cereals may have a higher GI than other, unhealthier foods such as cakes and biscuits. This doesn’t mean we should replace fruit and vegetables with lower GI cakes, because you will be depriving yourself of nutrients and anti-oxidants. Using GI to make good food substitution choices can be beneficial though, eg, having weet-bix instead of cornflakes, or grainy bread instead of white.