Carbohydrates
6-minute read
Key facts
- Carbohydrates are a macronutrient found in food.
- They provide your body with energy and helps your body function.
- Carbohydrates are found in different foods in 3 different forms — sugars, starch and fibre.
- Some sugars break down more slowly than others (low GI foods) and are generally better for you.
- Carbohydrates, especially low GI, high fibre foods, are important to have in your diet.
What are carbohydrates?
In food, there are 3 major nutrients that give us energy:
Your body prefers carbohydrates as a source of energy. Carbohydrates are also important for the function of your:
- brain
- muscles
- immune system
- digestive system
Carbohydrates are found widely in our diet. They are found in:
- all fruits and vegetables
- breads and grain products
- dairy foods like milk, yoghurt, custard and ice cream
- sugar and sugary foods
Some foods that contain carbohydrates also contain:
Types of carbohydrates
There are 3 main types of carbohydrate:
- sugars
- starches
- dietary fibre
Your body cannot digest the carbohydrate in dietary fibre. However, it’s still important for your diet.
Fibre can be soluble or insoluble. Soluble fibres can be absorbed into your blood stream, where they can reduce your cholesterol levels.
Fibre also helps keep your gut healthy and help with bowel movements.
What foods contain carbohydrates?
Different types of carbohydrate are found in different types of foods.
Sugar
Sugars include:
- glucose
- sucrose
- fructose
- lactose
Some sugars are naturally found in foods. Fructose is primarily found in fruits, while lactose is found in milk.
Sugars can also be added to foods. Sucrose is usually added to different food products.
Foods that contain added sugar include:
- white sugar and brown sugar
- honey
- fruits
- lollies
Starch
Carbohydrates rich foods that are healthy include:
- legumes and peas
- corn
- potatoes and sweet potatoes
- wholegrains grains like rice, oats and barley
- breads
- rice and pasta
- wholegrain breakfast cereals such as porridge and bran flakes
- milk and yoghurt
Dietary fibre
Dietary fibre is found in many different plant foods, including:
- vegetables
- wholegrain foods
- legumes
- fruits
- nuts
- seeds
How are carbohydrates digested?
The digestion of carbohydrates starts in your mouth, where they are broken down by your teeth and saliva. Digestion then continues in your digestive system (stomach and intestines).
When digested, carbohydrate containing foods break down into simple sugars, such as glucose. These sugars are then absorbed into your bloodstream and can be used for energy.
Some sugar is converted to glycogen and stored in your liver. Between meals, liver glycogen is converted back into blood glucose as an energy supply.
Glycogen is also stored in muscles for muscle activity. Carbohydrates that are not used for energy or glycogen storage are converted to fat.
Dietary fibre cannot be digested by our bodies. It passes through the intestine.
Glycaemic index
The glycaemic index (GI) is used to rank foods based on how quickly carbohydrate foods are digested to glucose.
Low GI foods are broken down slowly. The glucose, from these foods is released into the blood over several hours. This can be helpful for people with diabetes — low GI foods help to keep your blood glucose levels stable.
High GI foods are digested rapidly and give you a quick blood glucose spike.
The GI of a food depends on different factors, such as:
- the type of starch it contains
- the type of fibre it contains
- how much fat is in the meal
How much carbohydrate should be in my diet?
A balanced diet includes foods from all the different food groups, including carbohydrates. Carbohydrates are very important in your diet.
Low GI foods are good everyday food choices. Low GI foods break down slowly and may help you feel full for longer. They will also increase your blood glucose levels more steadily than high GI foods.
It’s also important to look at the overall nutritional value and carbohydrate content of a food item, not just the GI value. Junk food with a low GI is still junk food.
It is best to choose carbohydrate-rich foods that are healthy and full of dietary fibre. Try to limit your intake of snack foods, as they are low in nutrients and high in:
- kilojoules
- saturated fat
- sugars
- salt
Carbohydrates in many snack foods are highly refined. You should only eat foods like biscuits, sauces and confectionery (lollies) in small amounts.
The Australian Dietary Guidelines recommend that adults eat:
- 4 to 6 serves of grains each day — one serve is equal to a cup of cooked rice or one slice of bread
- at least 5 serves of vegetables and legumes each day — one serve is equal to half a cup of potato, beans or cooked orange vegetables or half a cup of legumes (beans or lentils)
- at least 2 serves of fruit each day — one serve is equal to a piece of medium sized fruit, such as an apple
Resources and support
You can learn more about recommended carbohydrate intake on the Eat for Health website.
You can call the healthdirect helpline on 1800 022 222 (known as NURSE-ON-CALL in Victoria). A registered nurse is available to speak with 24 hours a day, 7 days a week.