What is a carb?

Carbohydrates are often the main source of energy in our diet¹. When you eat and drink carbohydrates, they are broken down into glucose, increasing the level of glucose in your blood². Therefore, the amount and types of carbohydrates that you consume can directly affect your blood glucose levels.

There are three main types of carbohydrates in food. Knowing what foods these are found in and how much of each to eat can be confusing. Here we explain these carb types in more detail, to help you make more informed choices when planning your meals and snacks.

Complex vs simple carbs

Carbohydrates are made up of lots of sugar molecules joined together³. Simple carbs are made up of either one or two sugar molecules joined together, for example, glucose, fructose and lactose. Simple carbs are broken down quickly, and so cause a faster and shorter increase, or a ‘spike’, in blood sugar levels⁴.

Complex carbs, on the other hand, are made from many simple sugar molecules joined together. For example, starch is made up of three glucose molecules attached to each other³. Complex carbs are broken down more slowly, therefore they release a more steady supply of glucose over a longer period of time⁴.

Starch - complex carb

Foods high in starch include vegetables like peas, corn and potatoes⁵, dried beans, lentils, and grains like oats, barley and rice. The grain group can be broken down further into whole grains or refined grains. Whole grains are the healthier choice as the refining process removes some of the goodness contained in the outer two layers, including fibre, B vitamins and minerals, and essential fatty acids. Whole grains take longer for your body to break down and are slower releasing than refined starches.

Fibre - complex carb

Fibre comes from the indigestible part of plant foods and includes fruits, vegetables, whole grains, nuts and legumes. Fibre contributes to digestive health and helps to keep you feeling full and satisfied after eating. For good health, aim to eat between 25-30g of fibre each day. Good sources include: beans and legumes, fruit and vegetables, whole grain pasta and bread, oats, and nuts (but watch portion size as nuts are high in good fats and calories).

Sugar - simple carb

There are two main types of sugar – naturally occurring sugars found in fruit and milk and sugars added to processed foods. Sources of added sugar to look out for include: raw sugar, brown sugar, corn syrup and high fructose corn syrup, glucose, fructose, sucrose, fruit juice concentrate, honey, maple syrup, molasses. On nutrition labels "total sugars" refers to both natural and added sugar. Try to avoid some of the most common refined sources of simple carbs, like cakes and biscuits, and look for healthier alternatives like dried fruit.

How much to eat of each carb?

Foods that are higher in fibre and wholegrains, rather than refined carbs or those with added sugars, are better for our overall health¹. It is recommended to get the majority of your carb intake from foods high in fibre, such as wholegrain bread, fruit, vegetables, nuts and seeds². Try to eat less foods that contain highly processed, refined carbohydrates, such as sugary drinks, white bread, sugary cereal, cakes and biscuits².