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What Are Macronutrients: The Basics

by James Anderson
Posted: November 17, 2015

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What are macronutrients and why should I care?There are many people who believe themselves to be experts on nutrition these days, but a lack of scientific basis is becoming a real problem when considering nutritional advice.

I’d like to change that by starting with some education about the basics of food as I believe that it is of paramount importance that we all have at least some knowledge of what goes into our bodies so we can take a little more responsibility for the outcome.

Today we’re starting with macronutrients. Macronutrients by definition are the structural and energy-giving caloric components of our food. These include carbohydrates, fats, and proteins. We also have micronutrients, which are the vitamins, mineral, trace elements, phytochemicals, and antioxidants that make up each of the macronutrients - vital for good health and wellbeing.


So, what exactly is protein?

A protein molecule is a group of amino acids, and amino acids are the building blocks of muscle. So it stands to reason that protein is an essential part of building, or at the very least maintaining muscle.

There are 20 amino acids in total, 9 essential and 11 non-essential and each protein molecule contains different ratios of these.

In terms of calories, each gram of protein contains 4 kcals of energy and although protein is a great source of energy, it’s not the bodies primary or preferred source of energy.

Why do you need it?

Aside from helping maintain and build muscle, protein is essential for growth and repair of all the cells in our body. This means that adequate protein will help support healthy skin, nails, hair, organs and even teeth.

For those of you who exercise, protein is paramount to ensuring that the damage caused will be repaired and rebuilt to help your muscle cells adapt and become even stronger for your next workout.

Finally, protein plays a huge role in hormone production and maintaining a healthy immune system. But there are other benefits too.

Protein is the most satiating macronutrient, which means that it keeps you fuller, for longer. This is because is takes longer for our body to break down and digest protein. Not only that, protein has the highest ‘TEF’ (aka the Themic effect of food), which is basically how many calories you burn digesting the food.

Protein is much higher at 20-30%, opposed to 2-3% for fats and 6-8% for carbs. Meaning for every 100 calories of protein, 20-30 of those don’t even touch the sides as you burn them off in the process of digestion!

Where can I get my protein?

For carnivores, it’s pretty simple.

  1. Any red meat
  2. Any white meat
  3. All types of fish (oily and non-oily)

For vegetarians who eat eggs and dairy, you’ve still got plenty of great options in the form of eggs (whites and whole). dairy products such as milk, cheeses, yoghurts; and dairy or egg-based protein powders.

And for vegans, you can most definitely get enough protein, it just takes a little more planning. Think beans and pulses such as lentils, chickpeas, kidney beans etc., plant-based protein powders and miso, soy, and tempeh products. Grains such as quinoa, buckwheat etc; and nuts such as almonds, cashews, walnuts and pistachios.


What are carbs?

All carbohydrates are formed from carbon, hydrogen and oxygen, but in different ways. Like protein, each gram of carbohydrate contains 4 kcal of energy. The types of carbohydrates are:

  1. Monosaccharides - simple sugars such as glucose, galactose and fructose - basic forms of carbohydrate that cannot be broken down any further.
  2. Disaccahrides - Disaccharides are two monosaccharides that are joined together and include sucrose, lactose and maltose.
  3. Polysaccharides – These are many monosaccharides joined together, such as amylose and amylopectin.

N.B. There are also oligosaccharides which are smaller polysaccharides, but for the purposes of simplicity, we can just group these together.

What do they do?

Carbohydrates are primarily used for fuel as the preferred energy source for the body and although low-carb advocates will state that your body can break down protein and fats to be used as a source of fuel, (which is true) this process is not very efficient and requires an intense amount of energy, which is why you often feel so sluggish and tired when you initially switch to a low-carb diet.

Adequate carbohydrate intake will also help ensure that your body doesn’t break down muscle tissue to use as a source of fuel. Muscle loss due to inadequate intake of food will cause a reduction in immunity as well as other functions in the body, so it’s critical that you try to maintain normal blood glucose levels through a balanced diet.

And if you’re into fitness then you probably need to know that your body requires glucose and glycogen for almost any activity, particularly high-intensity work, so carbs at the ready will play a critical part in ensuring that you not only perform at your best, but recover quickly, too.

Finally, many carb-rich foods provide some seriously good stuff – we’re talking fibre, vitamins, minerals and antioxidants.


The amount of carbohydrates you can eat (without putting on weight) depends entirely on the individual. Generally, leaner people carrying more muscle mass will have a better insulin sensitivity, meaning they can eat more carbohydrate while losing fat or staying lean. However, if you’re a little older though, or holding onto a little more weight, you may need to keep carbohydrates a little lower.

Where can I get carbohydrates?

I’m sure we can agree that finding carbs is never that hard, a fact that is both good, and bad. Good in the sense that you never have a problem finding them, and bad as we tend to overeat them because of this.

Breads, pastas, fruits, vegetables, lollies, cakes, milk, yoghurt….the list is long, but it’s important that you source quality produce to ensure you’re getting the essential nutrients and fibre from your carbohydrates.

This means that 80% of your carbohydrates should come from whole grains and vegetables, rather than cakes and sweets.

But I’m pretty sure you already knew that, right?


What is fat?

Like carbohydrates, there are many types of fat. Fat however, differs from carbohydrates and proteins as it contains a much higher caloric density with 9 kcal per gram, which is one of the reasons why intake needs to be more carefully monitored.

Types of fats are:

  1. Unsaturated
  2. Monounsaturated – including olive oil, avocado, nuts such as macadamias, cashews, almonds, peanuts and hazelnuts (as whole nuts and in oil or butter form.)
  3. Polyunsaturated – including seeds, sunflower oil and oily fish.
  4. Saturated – including red meat, dark poultry, full-fat dairy such as cream, butter and cheese, as well as tropical fats like coconut oil.

We should be aiming for roughly an equal mix of the two types of fat by getting a varied diet and rotating our food sources. This means getting around one-third of your fat from monounsaturated sources, one-third from polyunsaturated and one-third from saturated fats.

What do they do?

You might have heard the phrase “essential fatty acids” – these are vital to basic human health and function, as well as performance. The main use of fat in your body is to help with hormone production – particularly production and regulation of the sex hormones – testosterone and estrogen.

We’ve got fat in every cell in our bodies – mainly in the membrane, meaning that fat also has a critical role to play in keeping your cells strong, as well as maintaining healthy teeth, skin, hair and nails.

Many of the vitamins we eat (vitamins A, D, E and K) are known as “fat-soluble vitamins”, meaning that in order to be used properly, they need to be consumed in a diet that contains fat. No fat equals poor nutrient absorption. Fat can also be used as a source of energy, and while your body generally prefers to run off carbohydrate, lower intensity and longer duration exercise relies more on fat, which means neglecting your fat intake could lead to a drop in performance.

Any to avoid?

In small doses, trans fats won’t do you any major harm, but it makes sense to limit them as much as possible. You’ll find trans fats in fast food, cakes and pastries, takeaways and margarine products or those made with hydrogenated oil.


James Anderson

James is the owner of a women’s only tribe based at Bondi Beach that focuses on strength and conditioning team training for optimal outcomes and long-lasting solutions.

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