Carbohydrates, Fats and Proteins – what are they? Why do I need them?

Carbohydrates, Fats and Proteins – what are they? Why do I need them? Carbohydrates, Fats and Proteins – what are they? Why do I need them? Carbohydrates are the bodies energy source. They are in healthy foods such as grains, fruit, milk, legumes and vegetables. They are also in sugar and nearly all junk foods. 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 high in kilojoules, saturated fat, sugars and salt, and have very few nutrients.

Types of carbohydrates

Sugars, starches and some types of dietary fibre are carbohydrates. Sugars include:

  • glucose – in fruit, honey and some vegetables
  • fructose – in fruit and honey
  • sucrose – from sugar cane
  • lactose – in all types of milk including breast milk
  • maltose – in malted grains.

Starches are also known as complex carbohydrates. Starches can be found in:

  • legumes
  • nuts
  • potatoes
  • rice
  • wheat
  • grains.

Starches are also found in cereal products such:

  • pasta
  • breakfast cereals
  • flour
  • polenta
  • couscous
  • burgul (cracked wheat)
  • quinoa.

Dietary fibre is found in many different plant foods including:

  • vegetables
  • wholegrain foods
  • legumes
  • fruits
  • nuts
  • seeds.

There is not enough sugar in fruit and milk to be a problem. But the sugars and starches in many snack foods are highly refined. You should only eat biscuits, sauces and confectionery in small amounts.

Digestion of carbohydrates

Carbohydrates are digested in your small intestine. They are broken down into simple (single) sugars such as glucose and fructose.

These sugars are absorbed into the bloodstream and can be used for energy. Some sugar is converted to glycogen and stored in the 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 not used for energy or glycogen storage are converted to fat.



Fat are an essential part of our diet and is important for good health. There are different types of fats, with some fats being healthier than others. To help make sure you stay healthy, it is important to eat unsaturated fats in small amounts as part of a balanced diet.

When eaten in large amounts, all fats, including healthy fats, can contribute to weight gain. Fat is higher in energy (kilojoules) than any other nutrient and so eating less fat overall is likely to help with weight loss.

Eating less saturated and trans fats may help lower your risk of heart disease. When buying products check the labels and choose the varieties that are lower in saturated and trans fats and higher in poly and monounsaturated fats.

So a diet that is low in saturated fats and trans fats, but that also includes moderate amounts of unsaturated fats will help you stay healthy.

Image of man reading a food label at a supermarket to illustrate the importance of reading labels.

Saturated fats

Eating greater amounts of saturated fat is linked with an increased risk of heart disease and high blood cholesterol levels. These fats are usually solid at room temperature and are found in:

Animal-based products:

Dairy foods – such as butter, cream, full fat milk and cheese

  • Meat – such as fatty cuts of beef, pork and lamb and chicken (especially chicken skin), processed meats like salami, Some plant-derived products:
  • Palm oil
  • Coconut
  • Coconut milk and cream
  • Cooking margarine

Many manufactured and packaged foods:

  • Fatty snack foods (such as potato chips, savoury crackers)
  • Deep fried and high fat take away foods (such as hot chips, pizza, hamburgers)
  • Cakes and high fat muffins
  • Pastries and pies (including quiche, tarts, sausage rolls, pasties, croissants)
  • Sweet and savoury biscuits

Unsaturated fats

Unsaturated fats are an important part of a healthy diet. These fats help reduce the risk of heart disease and lower cholesterol levels (among other health benefits) when they replace saturated fats in the diet.

There are two main types of unsaturated fats:

Polyunsaturated fats:

  • omega-3 fats which are found in fish, especially oily fish
  • omega-6 fats which are found in some oils such as safflower and soybean oil, along with some nuts, including brazil nuts.

Monounsaturated fats:

  • found in olive and canola oil, avocados and some nuts, such as cashews and almonds.
An image of almonds to illustrate a potential source of monounsaturated fats.

Trans fats

Trans fats are unsaturated fats that have been processed and as a result, behave like saturated fats. Eating trans fats increases the levels of ‘bad’ cholesterol and decreases the levels of ‘good’ cholesterol in the body which is a major risk factor for heart disease. It is important to lower the amounts of trans fats you eat to help you stay healthy.

Trans fats are found in many packaged foods and also in butter and some margarines. Use food labels to compare foods and choose those with fewer trans fats.

It is great for health to replace saturated and trans fats with mono and polyunsaturated fats.

Source: Dietitians Association of Australia.


Cholesterol is a type of fat found in food, but also in our blood. Cholesterol has many important functions in the body but having high levels of the wrong type of cholesterol in the blood increases heart disease risk.

It was once thought that eating too many cholesterol-containing foods (such as eggs) was the major dietary cause of high blood cholesterol level. But we now know that eating too many foods containing higher amounts of saturated and trans fats is a bigger problem and has a much greater influence on blood cholesterol levels.

Source: Dietitians Association of Australia.


Proteins are astonishing nutrients because they are so fundamental to our very architecture as humans. Our cells and organs, our muscles, our connective tissue, and even our bones could not hold together as the key body parts they are without the help of protein. This importance of protein to our very structure is only one function played by proteins, however. Proteins are equally important to our metabolism because all enzymes in our body that help trigger chemical reactions are proteins. Many of our most important regulatory hormones, like insulin, are also proteins. So are many of the key molecules in our immune system as are the major molecules used to carry nutrients around our body. Whether they are structural proteins, immunoproteins, hormonal proteins, transport proteins, or enzymes, proteins are of utmost importance to our health. The importance of protein to our life is reflected in the term itself: protein is derived from the Greek term protos, which means “taking first place.”

Proteins are made up of smaller molecules called amino acids that are strung together by chemical bonds like beads on a chain. To become an active, functional protein, this string of amino acids folds in on itself forming a twisted and entwined three-dimensional structure. Proteins come in many sizes. Some chains of amino acids are quite small, like the hormone insulin that is only 51 amino acids long. Most proteins, however, are larger. Most of proteins in your body contain between 200-400 amino acids.

Amino acids are similar to simple sugars, insofar as they serve as the building blocks for all other molecules found within their nutrient category. Just as carbohydrates are composed of monosaccharides, proteins are composed of amino acids. And, in a manner similar to the digestion of carbohydrates, your body can break proteins down to amino acids during the digestion process, taking in only the small single amino acid unit, or sometimes a two or three amino acid unit. Like carbohydrates, amino acids are composed of carbon, hydrogen, and oxygen. However, unlike carbohydrates, amino acids also contain nitrogen. In fact, amino acids are your body’s primary way of getting nitrogen.

Feeling a little overwhelmed or confused. Yes I know exactly how you feel. You read this stuff and it does seem a little complicated. But there is an easy way to wade through all this information and simplify things for you. Limit the about of simple carbohydrates or added sugar in your diet. Don’t go over board on the fats side of things and make sure you are getting enough protein. Do these simple things and you will start to look and feel better. Unfortunately modern life doesn’t lend itself to having a balanced diet. Sadly due to rise of takeaway foods and highly processed packaged foods our diet nowadays is more about convenience rather than nutrition. My nutritionist is always on about eating your food from its natural packaging rather than out of a bag or a box. And when you break down some of these supposed health foods (in a box) you actually find out they are not as good for you as you first think. If you’re ready to take the first step in getting your health and fitness back contact us today to a arrange a free consultation.