Macronutrients: Fats, Carbs, and Proteins
10 min read

What are macronutrients? Breaking Down the Fats, Carbs, and Proteins Found in Your Food

If you’re familiar with the term macro tracking or counting macros you most likely know what the term macro or macronutrients mean, but if not you may be wondering what the heck are macronutrients and why do I need to know what they are?

What are Macronutrients?

Macronutrients, also referred to as macros are the big 3 nutrients that your body needs in large amounts every day to function and perform essential processes to produce energy and maintain several systems within the body. Macronutrients, meaning large nutrients are the most basic building blocks that your body utilizes to build, maintain and fuel every part of your body from pumping your heart, contracting muscles, maintaining bone density and much more.

There are 3 nutrients that are included when you hear the word macronutrient or macros. Those are carbohydrates, fats, and proteins. These provide your body energy in the form of calories and each are needed in different amounts depending on the persons energy needs, age, sex, activity level, and other health conditions.

  1. Carbohydrates provide 4 kcals/g
  2. Protein provides 4 kcals/g
  3. Fat provides 9 kcals/g

Fat is the most nutrient dense out of the 3 nutrients providing double what protein and carbs provide. Each of these 3 macronutrients are needed in varying amounts as they work together in many instances while also performing very different roles throughout the body.



Protein is an essential nutrient needed to perform many different processes throughout the body. Protein plays a structural role in tissues and acts as a building block to many parts of the body including cell membranes, organs, muscle, hair, skin, nails, bones, tendons, ligaments and blood plasma.

Protein is a large molecule made up of many smaller components called amino acids. There are two types of amino acids that make up protein molecules: essential and non-essential amino acids. Essential amino acids cannot be made by the body. As a result, they must come from food. The 9 essential amino acids are: histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine. Nonessential amino acids are ones that our bodies can produce, even if we do not get it from the food we eat. Nonessential amino acids include: alanine, arginine, asparagine, aspartic acid, cysteine, glutamic acid, glutamine, glycine, proline, serine, and tyrosine.


Protein Sources:

There are two common types of protein sources: complete and incomplete proteins. Complete proteins contain all 20 amino acids. Foods that include all 20 amino acids include red meat, chicken, seafood, eggs, milk, cheese, yogurt, quinoa, chia seeds, tofu and tempeh.


Incomplete proteins are foods that contain some of the essential amino acids but not all of the amino acids necessary. Some food sources of incomplete proteins are grains, nuts, seeds, fruits, veggies, beans, and legumes.


Protein Needs: The Recommended Dietary Allowance is 0.8 grams of protein per kilogram of body weight per day. For a person who weighs 150 pounds, that adds up to around 54 grams of protein per day. Individual needs will vary depending on age, activity level, medical conditions and health goals.


Protein Benefits: Protein is a key component to support healthy weight management as it increases feelings of fullness. A high-protein diet may promote lower energy intake through regulating appetite as it takes longer to digest, which in turn leads to potential weight loss over time.

Eating protein can boost your metabolism for a short while. That’s because your body uses calories to digest and make use of the nutrients in foods. This is referred to as the thermic effect of food (TEF). However, not all foods are the same in this regard. In fact, protein has a much higher thermic effect than fat or carbs — 20–35% compared to 5–15%.1

A high-protein diet also may help lower the risk of developing hypertension. A study published in the American Journal of Hypertension found that participants consuming the highest amount of protein (an average of 100 g per day) had a 40% lower risk of high blood pressure compared with those consuming the least amount in the study. High-protein snacks also can help maintain normal blood glucose levels which can be beneficial for those with type 2 diabetes.1



Carbohydrates – or carbs – are the body’s primary fuel. They provide energy for your muscles and the central nervous system during movement and exercise. Carbohydrates consist of fiber, starches and sugars and are essential food nutrients that your body turns into glucose to give you the energy to function. Complex carbs in fruits, vegetables and whole-grains are less likely to spike blood sugar than simple carbs. Your body can make glucose out of necessity from proteins using gluconeogenesis when under certain conditions such as fasting, high intensity training, and when consuming a high fat low carb diet such as a keto diet. 2

Most carbs are broken down into glucose, or sugar molecules. This doesn’t apply to dietary fiber, a type of carbohydrate that isn’t broken down and passes through your body undigested. Still, some fiber is fermented by bacteria in your colon where they essentially feed the good bacteria in your gut which can promote a healthy digestive system.

Some of the main functions of carbs include

  • Quick Energy: Glucose is the preferred energy source for your brain, central nervous system, and red blood cells as it is easily digested and absorbed.
  • Storing energy: Glucose is stored as glycogen in your muscles and liver for later use when you need energy.
  • Digestion: Fiber promotes healthy bowel movements.
  • Helps you feel full: Fiber fills you up after eating and keeps you feeling full for longer.

Types of carbs: Simple and complex

Simple Carbohydrates: Simple carbohydrates are easy for your body to break down and are used for quick sources of energy or glucose. Simple sugars are carbohydrate molecules that contain only one or two sugar molecules, also called saccharides which can be found in items that are on the sweeter side such as honey, maple syrup, agave nectar, molasses, milk/yogurt, and fruit. They're also added to processed foods to enhance the flavor, texture, and shelf-life. You can easily identify simple sugars because they often end in the suffix "ose," like glucose, fructose, sucrose and lactose.

Complex Carbohydrates: Complex carbohydrates are longer, more complex carbohydrate structures that take longer for your body to digest and include starches and fiber. Complex carbohydrates are found in foods such as peas, beans, whole grains, and vegetables such as potatoes and corn. Fiber is a complex carb source that your body can’t break down. Most of it passes through the intestines, stimulating and aiding digestion. Fiber also regulates blood sugar, lowers cholesterol and keeps you feeling full longer. It is recommended that adults consume 25 to 30 grams of fiber every day.

Carb Needs: There isn’t a set amount of recommended daily carbs. Your age, gender, medical conditions, activity level and weight goals all affect the amount that’s right for you. Some health experts recommend 45-60% of your daily kcals come from carbs focusing on whole foods such as fruits, veggies and whole grains. Again, this is a recommendation and what works for one person is not always the best choice for someone else.



Fats used to get a bad rap and still might depending on who you talk to, but the science is always evolving and what we are learning now is that fats are not to be feared! There are several different types of fats and each one impacts the body a certain way, with some fats affecting the body in positive ways and others affecting the body negatively. Everything you need to know will be explained in the next few paragraphs!

Fat is an essential nutrient for human life, enabling a wide range of biological functions that keep us healthy and thriving – including energy storage, vital organ protection, and even cell structural support. Fat is vital for the body as an energy reserve, for insulation and protection of your organs, and for absorption and transport of fat-soluble vitamins.

Saturated Fats: These fats are long chains of singly bonded carbon molecules that are usually solid at room temperature and are primarily found in animal food sources such as beef, butter, high-fat dairy coconut oil, lard, heavy cream, lamb and cheeses. These fats sometimes get the “bad” rep. In excess, saturated fats may be associated with cardiovascular risk as it can increase cholesterol levels and may put you at a risk for heart disease. The American Heart Association recommends only about 5% of your daily kcals come from saturated fat. If you consume 2000 kcals/ day this is about 13g of saturated fat a day. Limiting saturated fat as much as possible is recommended if at risk for cardiovascular diseases.

Unsaturated Fats: These fats have at least one double bond causing the fat molecules to bend making these fats liquid at room temperature. There are two types of unsaturated fats; monounsaturated and polyunsaturated fats. The number of double bonds these molecules have is how they are named and put into these two categories; with monounsaturated fats having only one double bond and polyunsaturated fats having multiple double bonds.2

Unsaturated fats are known as the healthy fat as they can decrease your risk for heart disease. These healthier fats can be found in plant and fish sources such as olive oil, salmon, nuts/nut butters, avocados, sardines and tuna. There are two forms of unsaturated fats that are considered absolutely essential, meaning they cannot be created in the body and must be consumed through the diet to sustain vital functions. Omega-3s are needed at a higher amount, and claim the most health benefits of any class of fats. You can find them in flax seeds, chia seeds, fish, and algae. Omega-6s are needed in smaller amounts as they are essential but consuming large amounts may promote inflammation throughout the body. It’s worth noting, in a standard Western diet, we eat too much omega-6 because they are found primarily in vegetable oils, such as canola oil, corn oil, and sunflower oil – staples in modern, processed foods.

Trans Fats: There are two types of trans fats found in foods: naturally occurring and man-made trans fats. Naturally occurring trans fats are produced in the gut of some animals and foods made from these animals (milk and meat products) may contain small quantities of these fats. Man-made trans fats are created during food processing that adds hydrogen to liquid vegetable oils to make them more solid and shelf stable.3 The primary dietary source for trans fats in processed food is “partially hydrogenated oils."  These can be found in margarine, shortening, baked goods, doughs, and fried foods. Look for them on the ingredient list on food packages but many companies are starting to reduce their use of trans fats in products because of the potentially harmful effects these fats can have on consumer health.

Trans fats have been found to raise your bad (LDL) cholesterol levels and lower your good (HDL) cholesterol levels.3 Consuming these fats increases your risk of developing heart disease and stroke. It’s also associated with a higher risk of developing type 2 diabetes, so it is best to limit these as much as possible.

Fat Benefits:

  1. Fat is essential for the absorption of fat-soluble vitamins A, D, E, and K.
  2. Unsaturated fats have anti-inflammatory properties and may help reduce the risk of cardiovascular disease, developing certain types of cancers and even Alzheimer's risk.
  3. Omega-3 fatty acids also support cardiovascular health
  4. Fats digest slowly, especially compared to carbs, leading to increased fullness and satisfaction and may help aid in weight loss goals.


Keto Macros

Now that you know what macros are and how each are important for the body, let’s look at how the keto diet uses them to go from using carbs to fat as the primary source of energy.

A typical keto diet generally varies within the following ranges: 60-75% of calories from fat (or even more but 75% is usually the goal when wanting to reach ketosis), 15-30% of calories from protein, and. 5-10% of calories from carbs.

So, if you are aiming for 2000 kcals on a keto diet 75% of your intake would be from fats so that would equate to about 167g of fat/day or 1500kcals. Protein would be about 15% of your total kcals which would be about 75g of protein/day (300kcals) and carbs would be the remaining 10% of your total kcals which would come out to be 50g of carbs/ day (200kcals).

Tracking your carbs is going to be the most important part of the keto diet—but you can have a little more flexibility when it comes to your protein and fat macros. Carbs are the main macro that we really want to watch when doing a keto diet because this is the main macro that will prevent the body from being able to switch from burning carbs to fat as the main fuel source (more on this here… Insert link to keto article).

Everyone’s macros will look a bit different as individual needs vary based on gender, activity level, age, and state of health. Finding what works for you is the key to making this diet a long-term lifestyle so if you feel best with 5% of your intake from carbs go with it, or if you feel best with 20% of your intake from protein roll with it. As long as you are conscious about your carb intake and making sure you are staying in ketosis you will reap the benefits of the diet!



  1. Halton, T. L., & Hu, F. B. (2004). The effects of high protein diets on thermogenesis, satiety and Weight Loss: A critical review. Journal of the American College of Nutrition, 23(5), 373–385.
  2. Patricia, J. J. (2021, September 18). Physiology, digestion. StatPearls [Internet]. Retrieved January 6, 2022, from
  3. Trans fats. (n.d.). Retrieved January 6, 2022, from


  • Macronutrients are carbs, fats, and proteins found in the food you eat.
  • Our body needs these nutrients in large amounts every day to function and perform essential processes.
  • Everyone’s macros will look a bit different as individual needs vary based on gender, activity level, age, and state of health.

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