What Are Macronutrients?


Macronutrients are the largest class of nutrients that your body needs to function from day to day. These include carbohydrates, fats, and proteins. They are the bodies main source of calories, and each provide different functions for the body in terms of how they are used. Each macronutrient contains a certain number of calories per gram, with protein and carbs both having 4 kcal per gram and fat having 9 kcal/gram. Because of their functions within the body, macronutrients play a large role in the maintenance of body weight.


Possibly the most discussed macronutrient, protein serves a pivotal role in muscle growth and repair. Proteins work by being broken down by your body into amino acids, which are then rebuilt as new proteins and protein structures in your body. The amino acids link together in different shapes and structures of varying complexity.

There are 20 different types of amino acids, of which 9 are considered to be dietarily “essential”, which means that they can only be obtained through consumed through your diet. A protein that contains all 20 types of amino acids are called complete proteins.

In terms of what proteins do for your body, their primary functions include aiding with building and repairing body tissues and cells. They play an important role in the repair of muscle tissues after strenuous exercise, but also facilitate the creation of hormones and enzymes in the body. It is generally recommended that people get about 1 – 1.1 gram of protein per pound bodyweight each day.


Carbohydrates are derived from starches, sugars, and fiber, and should make up the majority of your diet. They are your bodies primary source of energy, but also help in building new muscles. When carbohydrates are broken down, a compound called glycogen is formed and is stored in the muscles to provide them with energy, when you exercise you use up this glycogen during muscle use. The lack of glycogen in your muscles is what causes them to fatigue. By eating simple carbs right after a workout, you can replenish your glycogen stores, leading to more efficient muscle repair.

Carbs come in two varieties, simple and complex carbs. The main difference between them is that complex carbs include fiber, whereas simple carbs do not. Examples of each would be corn syrup for simple carbs, and wholegrain bread or oatmeal.

It is recommended that carbs account for 45 – 65% of your diet.


Fats can cause a lot of confusion amongst first time dieters. It is often perceived that fats are bad for you and should be avoided, but this not true. It is true that fat is more calorie dense than either protein or carbs, but it should not be avoided. Fats are essential to your body, and you should try to have them account for 20% of your caloric intake.

Healthy fats take on important roles in your body, from aiding in brain function to acting as energy storage, it is very important for you to be getting enough fats, without them you’ll feel incredibly sluggish and cognitively won’t feel your best.

Where people often get the idea that all fats are bad usually stems from trans fats. Trans fats are an artificial form of fat created by the food industry to help in food processing. It can lead to higher levels of cholesterol in people and is not a part of any healthy diet. Healthy sources of fats are salmon, avodcados, and nuts.


If you’re wondering how much of your diet should be comprised of each macronutrient, check out our simple macro calculator to give yourself an idea.