What are Macronutrients? Our Complete Guide! 

Macronutrients are the three nutrients your body needs in large quantities to provide energy for all functions and exercise. These include protein, carbohydrates and fats. Micronutrients are vitamins and minerals that are also very important, but needed in much smaller quantities. 

But what are they for and how much of each macronutrient do you need in your body? Let’s find out with our complete guide to macronutrients! 

What are macronutrients?

Your macronutrients are nutrients your body needs for energy in order to perform everything from basic organ function through to intense workouts. These are nutrients your body can’t produce, and therefore come in the form of food. 

The macronutrients themselves are protein, carbohydrates and fats. Therefore it’s essential that your body gets these key components in the right levels to ensure you’re functioning at your best. 

These macronutrients contain energy in the form of calories. So whenever you look at the calorie content of food, know it comes in a mixture of either carbs, protein or fats. 

One gram of these macronutrients contain the following: 

  • Protein: 4 calories per gram
  • Carbs: 4 calories per gram
  • Fats: 9 calories per gram

Macronutrient food sources – how to get macronutrients into your diet

Macronutrient protein - how to get macronutrients in your diet

To ensure you’ve got a good idea of which foods you should be including in your diet to hit your macronutrient goals and ensure your body is working optimally. 

The majority of foods offer up a combination of the three macronutrients, however it’s a good idea to know which food offers up high levels of each, so you’re equipped to manage your macronutrient intake. 

High protein foods

In order to get a good serving of protein in your daily food routine, you need to be aware of which foods offer high levels of protein. So many people eat less protein than they should and, if you’re committed to fitness and supporting your overall performance improvement, then it’s really important you get the right amount of protein in your diet. 

Let’s take a look at high protein foods that can support you in achieving your daily goal.

  • Lean meats – chicken, turkey, pork, beef
  • Dairy – Milk, cheese, Yoghurt, quark, cottage cheese
  • Legumes – beans, green peas, soy beans, edamame, Lentils
  • Vegan meat alternatives (soy products) – Seitan, Tofu, Tempeh
  • Eggs – particularly the whites of the egg
  • Fish – Salmon, cod, haddock
  • Nuts and Seeds – Hemp Seeds, Chia Seeds, Almonds

If you aim to add a few portions of these foods to our daily food intake, it will go a long way to supporting your body in maintaining and promoting muscle growth. 

This is especially important if you’re working out regularly or trying something like body recomposition. Without amino acids to rebuild your muscles stronger, you’re not going to see the improvements and growth you hope for as quickly or as significantly. 

Food with carbohydrates

Carbohydrates are absolutely essential to providing your body with energy. Good sources of carbohydrates include the following: 

  • Whole grains: Rice, oats, barley
  • Dairy Products: Milk, Yoghurt, Cheese
  • Vegetables: Potatoes, Peas, high starch vegetables
  • Fruit: Bananas, Apples, Mangoes other high fructose fruit

Food with fats

Fats have gotten a bad rap in recent years due to the high calorie content, but they shouldn’t be dismissed. They are essential to keeping your body healthy and for key functions you body needs to perform to stay in tip top shape. 

Foods with fat sources are:

  • Oils – extra virgin olive oil, coconut oil, vegetable oil, Avocado oil
  • Avocadoes
  • Nuts and seeds: Almonds, cashews, chia seeds
  • Some fish: Salmon and herring
  • Dairy: Milk, cheese, yohurts

If you feel like you’re really focussed on achieving your fitness goals, then it might be a good idea to understand how many calories and macronutrients you should be eating. This article will help you calculate what you should be eating and the optimal amount of protein you should be consuming to support your goals. 

You can also use MyFitnessPal to help you keep track of everything you’re eating. 

Macronutrient functions

As we’ve mentioned above, finding out more about what macronutrients are includes understanding what functions they provide within the body. 

Each of the three macronutrients we’ve spoken about have specific functions that are vital to a healthy body. 

When a macronutrient is digested, they’re broken down into cellular level and are then utilized by your body for key functions. Let’s find out more about what each one does. 

Let’s look at the key roles of the different macronutrients: 


Once you’ve digested protein, it’s reduced down to amino acids. 

There are twenty amino acids which can be found in foods, which all have important roles within the body [1]. When you hear about a food offering up a “complete” protein profile, it means it contains all 20 of these amino acids. This is important for our veggie and vegan friends out there, as many plant-based proteins don’t offer a complete profile. 

Of these 20, nine of the amino acids are essential and must be consumed for a healthy body. As a general rule, go for those complete proteins and try to enjoy varied protein sources. 

These are the main functions of protein in the body [1]. 

  • Repair and growth: Amino acids can help to rebuild muscle that’s been damaged in exercise, repair the muscle tissue and grow it bigger. 
  • Structure: Amino acids are also the building blocks to cell membrane, organs, hair, skin and nails.
  • Hormones: Your body needs protein to create key enzymes and hormone that are essential to normal function

Related article: 12 Protein Rich Vegan Foods 


The majority of carbs are digested and broken down to glucose. This can be done at different rates depending on the complexity of the carb [2]

The exception here is dietary fiber, such as Konjac Root, which is an extremely complex carbohydrate which cannot be broken down with digestion and passes through the body without being digested. 

The key functions of carbs are as below [2]

  • Immediate energy – Your body will primarily utilize glucose as a source of energy. This includes moving around, but also for your brain and central nervous system. 
  • Stored energy – Your body can take glucose and store it in your muscles as glycogen for use when you need it later on. 
  • Satiety – This is a fancy word for feeling full. The fiber in carbohydrates fill you up and keep you feeling full, especially if they’re complex carbs that take longer to digest and break down. 
  • Aids digestion – Fiber is key to the digestive process and promotes healthy bowel movements. 


Fats, also known as lipids, are digested and reduced down to fatty acids and glycerol [3].

The main functions of fats in the body are: 

  • Promoting cell membrane health – Lipids are a key part of this element of your cells
  • Energy storage – Fat on the body is stored energy which can be used when you are burning more energy than you have eaten in calories. It’s always healthy to have some fat stored away
  • Vitamin transport – Fats can be used to transport certain vitamins, including A, E, D and K
  • Organ protection – fat can help to insulate and protect the organs

Macronutrients vs Micronutrients – what’s the difference? 

As we touched on briefly earlier in this article, Macronutrients and Micronutrients are both very important, but quite different. 

Macronutrients are fat, carbohydrates and protein and are needed in much higher amounts than micronutrients in order to continue with normal bodily function. 

Micronutrients are made up of vitamins and minerals, of which there are 13 of each that are absolutely essential, which means you need to get them from your diet. Your body cannot produce them itself.

Among other things, Micronutrients help your body to grow, allow you immune system to function, support energy metabolism and more [4].

We’ve also established that a key part of macronutrients is that they make up your caloric intake. Conversely, Micronutrients do not. They don’t contain any calories and actually extract energy from food in order to facilitate your normal bodily functions [4].

Macronutrient split – how much carbs, protein and fat should be in my diet? 

As we’ve established, macros are super important and it’s important you get enough of each of them in order for your body to function in a healthy way. 

For this to happen, it’s important to eat a varied diet. 

The United States Department of Agriculture (USDA) Dietary Guidelines recommend the following macronutrient split for adults [5]

  • Carbs: 45–65% of your daily calories (Minimum of 130g a day)
  • Protein: 10–35% of your daily calories
  • Fat: 20–35% of your daily calories

Of course, this is a great place to start to support your overall health, and ensuring you’re getting everything you need for a balanced diet (along with plenty of micronutrients from a varied diet including veggies and fruit etc). 

However, if you’re looking to start to develop muscle and strength in the gym, or support your fitness goals, you do need to ensure you have a more targeted approach when it comes to macronutrients. 

The number of macronutrients and calories you need varies from person to person, depending on things like sex, amount of exercise you do, age and more. 

So, if you suddenly started doing more exercise, going to the gym five times a week and moving more, it’s important you know what your calorie and macronutrient intake is to support you in this. 

To work out how many calories you should be consuming each day, and how many macronutrients you need to support your goals, this article will help you to plan out what you need. 

How to track macros

One of the ways you can ensure you’re achieving your food intake goals correctly is to find out how to track macros. 

This way, you can rest assured you’re getting your calorie intake, along with your macro and micronutrients too. 

This method works for some people, but it may not work for you, especially as some people can become fixated on what they’re eating and overly restrictive. If you think you might be prone to this, learning how to track macros might not be the best solution for you. 

If you do think it will work for you, then we recommend using an app to track macros, like MyFitnessPal. 

We’ve used this many times, and like how easy it is to scan foods in and keep a track of all your nutrients, not just your macros. 

You can also set personalized macronutrient and micronutrient goals that you can work towards each day to ensure you’re hitting your targets. 

Having structure around this type of thing can really help if you’re starting out on a fitness journey or have specific goals in mind, so it’s something we recommend. 

What are Macronutrients? The final word

As we’ve highlighted, macronutrients are more than just fats, proteins and carbs. They’re extremely important to your overall health and to your fitness journey too. 

It’s important you’re getting enough of them to ensure you’re healthy and achieving all your gym goals too. 

Try finding out how much of each you should be eating each day and tracking them for a while to see if your performance in the gym improves. Leave your results and thoughts in the comments below! 


gymgirlfit was created by health and fitness enthusiasts, with backgrounds in powerlifting and writing. We've written for a number of well-known fitness publishing companies.

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