The beginner’s guide to macronutrients

It’s Macros Month on Sarah in Shape

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What are Macros?

If you’ve been on the internet ever, I’m sure you’ve heard of the term “macros.” You might have read people talking about counting their macros, the macros in a healthy meal or the power macros have when it comes to weight loss. They’re a pretty hot topic on Instagram and bodybuilding forums, but don’t just dismiss them on that basis! But what actually are macros?

“Macros” is short for macronutrients: protein, fat and carbohydrates – and fibre, depending on your information sources. They are what make up the energy or caloric content of food. When you look at food labels, the magic number up the top that says calories (or kilojoules if you’re in Australia like me) is the sum of the energy contributed by the macronutrients found in that food.

The different macronutrients contribute different amounts of energy: 

  • 1g of protein has 4 calories or 17 kilojoules
  • 1g of fat has 9 cal or 37kj
  • 1g of carbohydrates has 4 cal or 17kj


Carbohydrates, in the form of grains, legumes and some vegetables, are a food source that has kept the population fed and satisfied since the beginning of agriculture. They’re basically the reason humans have been able to survive and prosper for as long as we have. 

History aside, there is a whole lotta’ mixed opinions emerging about carbohydrates. And there seem to be more carbohydrate options than ever before. High-carb, low-carb, no-carb, high GI-carb, natural-carb, refined-carb, healthy-carb, Low GI-carb – which, witch is which? But enough tongue twisters.

Scientifically, carbohydrates are molecules that have carbon, hydrogen and oxygen atoms (carbo = carbon, hydro = water from hydrogen and oxygen H₂O). In food, they’re found as sugars, starch and fibre; each of these reacts differently in the body. But they must end up as simple sugars before the body can use them. 

Whether you love or loath carbohydrates, biologically they are the preferred source of energy of the body, and in particular, the brain. This macronutrient is broken down into simple molecules, namely glucose, that the body can use in the majority of its functions. The more complex the molecule, the more work the body has to put into breaking it down. 

To learn more about the different types of carbohydrates, how they work in the body, and a list of healthy carbohydrate foods, download the carbohydrate cheat sheet: 

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Proteins are essentially the building blocks of the body and are necessary for growth and repair. It’s the main component of skeletal muscles and many other body structures. Protein molecules are made of long chains of amino acids, of which there are nine essential types.

You can find protein in both plant and animal food sources, however, the amino acid composition in animal sources is more similar to that of the human body. That said, complete proteins (those that contain all nine essential amino acids) can certainly be found in plant-based combinations.

A high protein diet has been shown to help with weight loss, weight maintenance and satiety. The rapid success of high protein, low carbohydrate diets has helped protein gain Royal-like status (I’m sure you’ve heard the phrase, protein is king). The food industry has experienced a complete shift in marketing, with foods considered to be healthy usually advertised as high in protein. 

Protein is officially in fashion. A scroll down any health-conscious Instagram feed will undoubtedly show protein balls, protein shakes, protein cakes, protein oatmeal, protein ice cream and just about anything else you can squeeze extra protein into. 

But if there’s one thing we’ve learnt from popular food crazes involving macronutrients, they do NOT always result in your best health (the low-fat epidemic, anyone?). To learn more about protein, what the body does with excess protein and a list of nutritious food protein sources, download the cheat sheet:


Fats, also known as lipids, are one of three essential macronutrients in the diet. They can be divided into triglycerides (which included saturated or unsaturated fats), sterols (the most common type is cholesterol), and phospholipids (found in the body’s cell membranes). Fat is something our body needs to survive; lipids are used in cell membranes, hormones, fat-soluble vitamins (A, D, E and K), and also as an energy source. It even helps us to feel full. 

But fat does have the highest energy density of the macronutrients with 37 kilojoules/9 calories per gram. That’s compared to the 19 kilojoules/4 calories per gram of protein or carbohydrates. This is the reason it was so easy for the diet industry to demonise fat as the route cause of the obesity epidemic. The very same epidemic that has all but gotten worse, despite the wide range of fat-free food alternatives available today. 

Fats are to thank for a lot of the taste, smell and mouth feel of most foods. It’s part of the reason that bad foods tend to taste so darn good. It’s also the reason that low or no fat alternatives of food generally taste like they’re lacking something. 

There are a number of different fat types including saturated, unsaturated and trans fats. Cutting saturated fat out of the diet in exchange for refined carbohydrates is no good for your health. But replacing saturated fat for unsaturated fat is marvellous for your arteries. To find out more about the different types of fat, and a list of healthy fat-containing foods, download the healthy fat cheat sheet: 

What is macro counting? 

Macro counting is similar to any food or calorie tracking. But it’s based much more on the type of food you eat as opposed to just the energy or calories you eat. 

The problem with calorie counting (or calorie assuming), is that it places no focus on the quality or nutrients of what you’re eating, instead focusing on energy in vs energy out. While this approach has been scientifically proven to work, it can be difficult to sustain – and doesn’t always equal optimal health. 

Instead, macro counters focus on the ratios of macronutrients they consume. A relatively healthy diet would see roughly 60 percent of energy come from carbohydrates, 20 percent from fat and 20 percent from protein.

But someone trying to lose weight may switch that up, and get 40 percent of their calories from protein, 40 percent from carbohydrates and 20 percent from fat. While someone on a high protein diet might aim for 45 percent of energy from protein, 35 percent from carbs and 20 percent from fat. The combinations are endless, and the most effective ratios differ from person to person.

Let’s chat below! Did you know about the importance of macronutrients before reading this article?

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