What Are Macronutrients and Why Are They Important

Written by
Lisa @ 8fit
Written by
Lisa @ 8fit
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In this day and age, we are bombarded with fitness blogs, Instagram posts, and Facebook advertisements that throw around the term macros. Macros is the abbreviation for macronutrients. But, what are macronutrients, why are they so popular in the fitness and nutrition world, and what ratio is ideal for you? Our nutritionists will explain.

One of the main problems with traditional dieting is that calorie counting doesn’t take into account what you’re eating. Macros can be a key player here, helping us quantify how much we eat as well as what we eat. Thinking about macros instead of calories — something 8fit meal plans take care — helps shift you into a healthier, more well-rounded way of eating.

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What are macronutrients?

The human body and all of its impressive mechanisms are quite complex, meaning that it requires a variety of nutrients in order to function optimally. What we eat is essential for meeting these needs. Macronutrients help us grow, develop, repair, give us energy, and make us feel good. They each have their own role and functions in the body.

Macronutrients refer to the three basic components of every diet — carbohydrates, fat, and protein — with a bonus fourth, water. Macro, meaning “large,” alludes to the fact that these nutrients are needed in larger quantities. Almost every food has a combination of macronutrients, but the difference lies in the composition of these macronutrients.

The macronutrient that has the highest percentage in each food will determine how it is classified, e.g. as protein, carb or fat. For instance, avocados consist of about 70% fat, 8% carb, and 2% protein, so even though they contain some of the other macros, they would be classified as a fat. Another example would be an apple which consists of about 95% carb, 2% protein, and 3% fat. If you didn’t guess it already, that meals apples are classified as a carb.

List of macronutrients


Carbs are made up of chains of starch and sugar that the body breaks down into glucose. These are the body’s main source of energy and the brain’s primary source. This is important to know because, since your brain requires fuel at all times in order to function, your body is very efficient at storing glucose (in the form of glycogen) in the liver and muscles.

Good sources of carbohydrates:

  • Whole grains (brown and wild rice, oats, amaranth, whole wheat)

  • Starchy vegetables (potatoes, sweet potatoes, corn, beets)

  • Legumes (beans, lentils, chickpeas, peas)

  • Fruits (apple, oranges, berries, pear, banana )


Fats are needed for brain development, making hormones and aiding in the absorption of fat-soluble vitamins (A, D, E, K). They have the highest calorie count per gram, meaning that they require more energy to burn, but at the same time, are helpful for increasing feelings of satiety, meaning they will keep you fuller for longer.

Good sources of fat:

  • Avocado and avocado oil

  • Olives and olive oil

  • Full-fat dairy and organic, grass-fed butter

  • Nuts (almonds, walnuts, cashews)

  • Seeds (chia, pumpkin, flax)

  • Fatty fish (salmon or trout)


Protein provides amino acids, which are the building blocks of cell and muscle structure. In total, there are 20 types of amino acids, nine of which are essential, meaning that your body requires them from food. Protein in the body is used beyond just muscle — it is the core component of organs, bones, hair, enzymes, and all tissue. Protein also helps support a healthy immune system.

Good sources of protein (organic preferred):

  • Fish and seafood (salmon, tuna, white fish, shrimp, crab, oysters)

  • Poultry (chicken and turkey)

  • Lean and organic meat (pork, beef, lamb)

  • Eggs

  • Dairy (minimally processed cheese, unsweetened yogurt, and non-dairy alternatives)

  • Tofu and soy products (minimally processed)


Water doesn’t contain any calories or nutrients, but it is still considered to be a macronutrient since we require it in large amounts. In fact, water makes up a large portion of our bodies. It serves as a carrier, helping to bring nutrients to cells and removing wastes. It regulates our body temperature and assists in metabolism.

The Institute of Medicine recommends about 13 cups of water (about three liters) for men and about nine cups (or 2.2 liters) for women. But this can vary according to activity level, environment, medical conditions, and alcohol consumption (which is dehydrating). Not sure if you get enough water? One of the best ways is to track it.

Macronutrient ratios

Now that we’ve answered, What are macronutrients?, let’s talk about ideal macro ratio ranges. Just like diet and fitness, macronutrient ratios are not one-size-fits-all. There is no ideal macronutrient ratio that suits everyone and your needs will change according to different factors in your life. Some people may do better on a lower carbohydrate diet, while someone else may feel more energized on a higher fat diet. In general, aim to have more carbs on the days that you’re more active and if you’re sedentary, you may see better results on a higher protein meal plan.

Another reason we don’t recommend a very specific macronutrient ratio is that it doesn’t say anything about the quality of the nutrients. A ratio only takes the number of macronutrients into account which means that carbs from white sugar and quinoa are handled the same way. The best thing you can do is…

Trying different macronutrient targets allows you to determine which levels work best for you. These ranges can vary depending on which type of diet you are following. Here are some examples of macro ranges:

Standard diet macros range:

  • Protein: 10-35% of calories

  • Carbs: 45-65% of calories

  • Fat: 20-35% of calories

Low-carb diet macros range:

  • Protein: 20-30% of calories

  • Carbs: 30-40% of calories

  • Fat: 30-40% of calories

Keto diet macros range:

Macronutrients calculator: How to calculate macronutrients

Time to put our nerd caps on! A calorie is a unit used to measure the energy-producing value of food but this is not the most accurate measure. To get technical, a calorie is defined as the amount of heat necessary to raise the temperature of one gram of water, one degree centigrade.

Each macronutrient has a different calorie level per gram weight.

  • Carbohydrate = 4 calories per gram

  • Protein = 4 calories per gram

  • Fat = 9 calories per gram

The total calorie content of food depends on the amount of carbohydrate, protein, and fat it contains. As you can see, fat is the most concentrated source of energy, yielding 9 kcal per gram. This is where those old school low-fats diets originated. The reasoning was based on the notion that if you remove the higher calorie per gram macronutrient, it would be easier to reduce the volume of food. However, this is flawed since fat is actually very satiating and can help promote weight loss when eaten in moderation.

Nutrition facts label

Nutrition information is often listed in grams, but we’ll teach you a little trick that will make you a Macro Master. Simply multiply the grams of each macro by the number of calories per gram. Then, add these numbers together to determine the total calories in an item.

Here’s an example, say you know that a granola bar has:

  • Total fat: 6g

  • Total carbohydrate: 25g

  • Protein: 10g

Now let’s plug it into the calorie level per gram, of each macronutrient….

  • Fat: 6g x 9kcal per gram = 54kcal

  • Carbohydrate: 25g x 4kcal per gram = 100kcal

  • Protein: 10g x 4kcal per gram = 40kcal

This makes the total calories about 194 kcal. Guess what? This health bar is not even healthy at all! Its main source of carbohydrate is from sugar! This is why it’s always important to check the nutrition label.

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Macronutrients vs. micronutrients

Unlike macronutrients, micronutrients (vitamins and minerals) are required in very small amounts but are still necessary for normal body functioning. They enable many chemical reactions in the body but don’t provide calories. Vitamins are essential for normal metabolism, growth, and development, while minerals are mainly needed as co-factors or the function of enzymes in the body. Focus on a wide variety of colorful foods to meet your micronutrient quota.

To make macros easy, sign up for 8fit and try one of our healthy recipes today.

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