Calories and Macros - what you need to know.

Calories and macros are two essential parts of nutrition. Before learning more, we need to know the basics of these, how they affect our bodies, how they impact our health and nutrition and how they play a role in everything that we do. The words 'calorie' and 'macro' have turned into buzz words on social media and there is so much confusion stemming from misinformation and misunderstanding, so let's break them down...

What is a Calorie?

A calorie in its most simple explanation is a unit of energy. In nutrition, it refers to the energy in the food we eat and the drinks we consume. In regards to us, calories are the fuel that is used in all of our physical activities. Our bodies store the amount of calories we consume and then burns those same calories as fuel.

Our bodies have a Basal Metabolic Rate (commonly referred to as our metabolism) which is the MINIMUM amount of calories our bodies require to function. If you stayed in bed for 24 hours and did nothing, this is basically how many calories you would burn. From there we add on work, exercise, eating, day to day movement and activity, so own top of our BMR we need to make sure our bodies have adequate fuel (calories) to function well.

Why is this important? When fuelling our bodies, there are foods higher in calories and also foods that have much lower calories. When choosing food, we get more bang for our buck choosing lower calorie foods that are higher in nutrients and very filling - rather than high calorie foods with little nutrients that aren't filling. Foods like lollies are easy to over consume because they do not have any protein or fibre (which help keep us fuller) but are very high in calories, so it can lead to overconsumption and weight gain.

So... Why are calories important in weight management?

If we eat the exact same amount of calories as we burn, we remain in maintenance (neither gaining nor losing weight.) If we consume more calories than we need to burn, we are in a caloric surplus. Our body then will store those excess calories as fat, to be used at a later time. If we consume less calories than what we need to function, our body then makes up the extra calories it needs to function by burning fat on our bodies as fuel.

All calories are made up by at least one (if not two or all three) macronutrients.

What is a Macro?

The word ‘macro’ today has become popular amongst social media and fitness influencers. But what on earth are they?

‘Macro’ is short for ‘macronutrient’. There are three macronutrient groups - Protein, Carbohydrates and Fats. All of the food we consume contains one or more of these macronutrients and they also contain micronutrients as well (the good stuff like vitamins, minerals, antioxidants etc.) The human body requires nutrients for energy, growth, repair and every functionality. These nutrients are either found in small or large amounts, a ‘macro’ being the larger amount! From each of the macronutrients our body receives energy in the form of calories. Such as;

  • In proteins, there are 4 calories per gram.

  • In carbohydrates, there are 4 calories per gram.

  • In fats, there are 9 calories per gram.

So what about the macronutrients themselves? I'm glad you asked...


This is the fan favourite of the macros - everyone is always worried about getting enough protein! Like the other 2 macros, protein is essential for our bodies - we cannot function properly without it. The USDA recommends 10%-35% of calories from our diet to come from a protein source. However, the typical Western diet typically contains more than this and not all of them are from optimal sources. (A topic for another day!)

So why is protein essential?

  • Protein is used for muscle growth and repair. This is why is especially important with exercise, as it helps repair and grow our muscles and also aids recovery.

  • Our body uses protein to make enzymes, hormones, and other body chemicals.

  • It’s an important building block for our bones, muscles, cartilage, skin, and blood.

  • Protein keeps us fuller for longer.


This poor guy gets such a bad rap but he's really a good guy, one that you should definitely be friends with! Our body requires carbohydrates in the largest amounts. It is recommended (by the USDA) that we get 45-65% of our daily caloric intake from carbohydrates. This percentage may surprise some people, especially as diets like Keto and Paleo (which both restrict the intake of carbohydrates) are in high prominence at the moment. So why are carbohydrates so important for our body, regardless of what social media trends and fat diets tells us?

  • Carbohydrates are our body's most preferred fuel source as they are the most easily metabolised.

  • Carbohydrates are predominantly found in grains, legumes, vegetables and fruits. Carbohydrates are classified as either simple or complex, which in other words refers to their chemical structure. Simple carbohydrates taste very sweet (such as fruit), while complex carbohydrates taste savoury (such as rice or potato!) Simple carbohydrates are metabolised more quickly and give us a spike of energy, whereas most complex carbohydrates are broken down and released into our bloodstream more slowly, giving us a more prolonged stretch of energy.

  • Natural forms of carbohydrates are usually high in fibre which is fantastic for keeping us full and keeping our digestive system regular. Highly processed or refined carbohydrates do not have the same benefits.

Also be aware that a LOT of highly processed foods, junk foods and nutritionally poor foods like chips, lollies, pizza, soft drink, biscuits etc are all classified as carbs too. This is why some information about "limiting carbs" may have crossed your path before - but be aware carbs are NOT inherently bad. We want to limit processed and refined carbohydrates and incorporate more plant based whole food carbohydrates.


Let's chew the fat lovelies! Again, industry trends have made us look at fats as the devil (all the low-fat food crazes over the years) and then suddenly embrace fats with open arms with the increase in Ketogenic, Paleo and Low-Carb diets. However, it’s important to remember that the consumption of fats for the human body is absolutely a necessity (just like the other two macronutrients!)

  • Fats are essential to our diets in helping absorb essential nutrients, vitamins and antioxidants.

  • Fats are also a huge energy source for the human body. (Our body uses fats when its preferred fuel source - carbs - has run out.)

  • They supply the body with fatty acids, such as omega-3 acids (which are used to promote heart health.)

  • Again, there are more optimal sources of fats than others. Try and limit deep fried foods or foods high in trans fats and opt for plant based sources of fat such as avocado, seaweed and algae, chia seeds, hemp seeds, flaxseeds, walnuts, edamame and nut butters.

Once you understand macronutrients and calories, it is easier to adjust your nutrition to suit your goals.

Please see the next blog post in this series which will get into food choices, micronutrients like fibre, vitamins and minerals and so much more!

Did this help clear up questions you had? Do you have more questions? I would love to know in the comments below!

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