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What are macronutrients? Complete guide with definitions, ratios, and free calculator.

golden apple, macronutrients, illustration

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What are macronutrients?

What are macronutrients?

Macronutrients are the larger nutrients that make up the calories in our food. When it comes to health and wellness it's important to know what macronutrients are, as well as how to calculate your own macronutrient ratio for nutritional needs.

Cellular respiration (the body’s ability to turn energy-dense nutrients into mechanical energy, or motion) all require the same molecule called glucose. Glucose can come from the 3 big macronutrients, plus a 4th you should probably know. They are:

  1. fat (9 cal/g)

  2. carb (4 cal/g)

  3. protein (4 cal/g)

  4. alc (7 cal/g)

Because of this, macronutrients can be thought of as the 3 big sources of energy. Once consumed each of these 3 macros are metabolized and converted into a usable form of “fuel” for the body.

The easiest way to conceptualize this is to think that everything you eat, from meat to potatoes all effect you blood sugar levels, and those levels then effects every other metabolic process in the body.

In the following pages we will dive into each macro and explore their unique properties and functions within the human body.



4 cal / gram

Insulin resistance, the inability for the body to process insulin, “is a metabolic disorder that is increasing worldwide and is associated with some of the most common diseases affecting modern societies including diabetes, hypertension, obesity and coronary heart disease.”

Carbohydrates, commonly referred to as “sugars” or “carbs”, these are the primary source of energy for all living organism. Carbohydrates provide “fuel” for all cells including the brain, muscles, and organs.

They directly influence mammalian blood sugar levels, playing an important role in a very important process called “cellular respiration” as well as the normal production of blood sugar called glucose.

Examples of carbohydrate-rich foods include grains, fruits, vegetables, and legumes. Carbohydrates are comprised of 2 main types: simple carbs and complex carbs/starches.

The easiest way to remember these is through two associations:

  1. simple carbs = processed sugars & refined flours

  2. complex carbs = grains & starches

Simple Carbs

The scientific term for sugars is saccharides. There are only 2 types of simple carbs: 1) monosaccharides, and 2) disaccharides. 7 The prefix “mono” means one, whereas the prefix “di” means two.

These two types of molecules are a specific kind of nutrient which can be chemically reduced easily and quickly to be used as energy for the body.

This type of fast absorption leads to increased sugar in the bloodstream which then initiates other bodily functions such as the release of the hormone insulin to help regulate the concentration of sugar in the blood.

Although most of us learn blood sugar spikes are bad, there are a few reason why one might want to consume a large amount of simple carbs. We will get to this later.


This type of saccharide is just one sugar molecule long, making it extremely easy for the body to use as immediate energy. Outside of their biological use for energy, most sugars not found in a monosaccharide form.11 There are 3 types of monosaccharides, glucose, fructose, and galactose.


Found in fruits and vegetables, as well as honey, corn syrup, and high fructose corn syrup. All plants and animals need glucose to survive. Mammals like humans can create glucose naturally through a process called glycogenolysis. 7


Fruits, vegetables, honey, and high fructose corn syrup are common examples of fructose. In a randomized controlled study published in 2000 called CARMEN which tested 398 obese adults for a 6 month period using 3 variations of carb-rich diets, concluded fats and dietary fat consumption is a greater indication of diet-related weight gain. 9


The primary source of galactose is in milk and dairy products, but almost always is linked to another sugar molecule, making it a disaccharide. 7


This is the second type of simple carb which consists of two sugar molecules chemically bound together, making it slightly more difficult to break apart than a monosaccharide molecule. However, it is still very quick and very easy absorbed into the bloodstream.

There are 3 types of disaccharides, maltose, sucrose, and lactose.

Maltose (glucose + glucose)

If you like beer then probably like it. If you don’t, than you probably don’t.10 Maltose is not naturally found in any foods outside of sprouted grains.7

Sucrose (glucose + fructose)

Table sugar. This is the most common form of processed sugar. It is formed naturally in most plants and can be harvested in high concentrations to use as an added sweetener.

Lactose (glucose + galactose)

Another form of milk sugar naturally found in dairy products. This is the most common form to find galactose. Simple carbs are excellent to replenish depleted glycogen and glucose levels after extensive or prolonged periods of exercise.

That said, an overload of carbs will spike the production of insulin, a hormone the body produces to help regulate blood sugar and signal to the liver to halt glycogenolysis.

If blood glucose concentration remains high for a prolonged period of time, other metabolic health issues are likely to occur. An example of this would be insulin resistance and type-2 diabetes.

Insulin resistance - the bodies natural ability to recognize blood sugar spikes and regulate them via the production of insulin - is hindered, often leading to type-2 diabetes, which is the bodies inability to produce insulin at all.

Lately there have been advancements in technology which allow a continuous glucose monitor (CGM) to be used by those who don’t have diabetes.

Although the technology was originally invested to help diabetic patients monitor and control their blood sugar levels, glucose monitors are a great way to learn about your body and how it responds to various foods and sugars you may consume.

Complex Carbs

These can be found naturally in starchy foods, nuts, seeds, and even people. Complex carbs are a type of sugar structure called polysaccharides. These are, as the name suggest, more than 2 sugar molecules long and make up the majority of the earth’s biomass.12 Polysaccharides can be found in 3 types; starch, glycogen, and fiber.


Starches are “the storage form of carbs for plants”. Some starchy foods have an interesting property where, once cooked and cooled, they turn into a more complex carb.

An example of this would be oats in oatmeal. Oats are a complex carb consisting of fiber and starch, but once heated and cooled they turn into an even more complex structure called a resistant starch.

Resistant starches have been shown to have a stabilizing effect on blood sugar and positive effects on insulin resistance.


If starch is the carb stores for plants, glycogen is the carb stores for animals. Housed primarily in the muscles and liver, glucose is turned into glycogen when too much sugar is circulating in the blood, and/or the animal has been sedentary for extended periods of time.

When we talk about athletic recovery, this is why we give the body a physical rest period - to make it easier for it to replenish lost stores.

If you think about it like your computer, when you have a ton of windows going at the same time, your computer will sense an immense amount of stress.

In most cases this is an issue of RAM and storage, and so the computer looks for ways to close a program or compress a window in an effort to decrease power and free up space. And it does this all automatically so you can have a better, more seamless experience in the digital world.

The body is very much the same way in the same regard. When we flood our body with nutrients it doesn’t need, the body begins to down-spin certain biological processes in order to maintain a state of homeostasis, or biological balance.

Historically our bodies did this to ensure survival in the real world, but in the modern world we often give our bodies more than what it needs. In times like this our bodies use what it can, and store what is left.

Yet to every uphill there is a down, and the body is a very efficient machine. When its ready to use those stores again the brain sends a signal to start processing glycogen in the liver back into glucose to be used immediately in the cell. 7


The easiest way to conceptualize fiber is to imagine a tree. Everything you see from the roots to the leaves is all fiber. If you looked at finer under an electron microscope you would see that the chemical structure kind of looks like a wall of hexagons. This structure makes it completely indigestible by humans.

Once consumed, fiber passes through the small intestine and into the large intestine where tiny microbiota begin to break it down.



4 cal / gram

Proteins are essential for the growth, maintenance, and repair of most tissues in all animals. Proteins are involved in various functions, such as building and repairing muscles, producing enzymes, hormones, and supporting the immune system.

Protein is one of the most fascinating and intriguing aspects of nutrition because there are hundreds of them, and we still discover newfound importance today.

Of the hundreds of amino acids found in nature, only 22 are essential to life, meaning they are found in all living organisms. What's even more fascinating is of those 22 amino acids essential to life, we humans only synthesize 13, the remaining 9 must come from our diet.

In this article we won't discuss all 22 essential amino acids, but we will provide a list of the 9 for ease of reference.

9 essential amino acids










Complete Protein

When we talk about protein most of us visualize a slab of meat, like maybe a burger or a steak. This type of protein is considered a complete protein, as it contains all 9 of the essential amino acids. Examples of protein rich food sources include meat, fish, eggs, (some) dairy products, legumes, nuts, and seeds. In general a person should consume roughly 0.5-1.0 grams of protein/lb of bodyweight.

Incomplete Protein

Most other forms of protein, like plant proteins you find in foods such as beans, are considered incomplete forms of protein due to their lack of the 9 essential amino acids.



9 cal / gram

Fats are concentrated sources of energy (calories), also called lipids, which aid in the absorption of certain vitamins, provide insulation and protection to our organs, and are essential to brain function and cognitive health.

Examples of healthy sources of fats include avocados, nuts, seeds, olive oil, and fatty fish. There are approximately 3500 calories in 1 pound of fat. Walking burns roughly 0.04 calories per step.

All living organisms on Earth have the ability to produce fat cells, but only vertebrates have the ability to produce fat stores in adipocytes (i.e. fat cells within the skin). That being said, fat mass in the human body can accumulate in 3 main types of stores: white, brown, and beige.

White Fat

Sometimes used in reference to “skinny-fat”, this type of fat sits inside the body and surrounds the organs. This is what causes the marbling of steaks and gives the visual appearance of “fat”. It’s primary role is to protect the body against physical harm and store lipids for later metabolism.

Brown Fat

This type of fat actually dissipate stores energy in the form of heat. It is how mammals are able to temperature regulate (thermoregulate). Babies have the highest concentration of brown fat which may be attributed to the drastic temperature change experienced at birth.

Adults loose the vast majority of their brown fat stores due to lack of use and can be attributed to living in temperature controlled environments as well as a lack of exposure to chronic cold.

Those who maintain chronic cold exposure, such as Scandinavian outdoor workers who experience extreme cold temperatures daily, maintain significantly greater brown fat stores.

Beige Fat

This is a very “new” type of fat with limited understanding and research. It shares similar thermoregulatory properties to brown fat, but remains slightly different ways of activation. Its presence seems to have a positive correlation with diabetic resistance due its their ability to process lipid and glucose into heat energy.


What are macronutrient ratios?

Use a pre-set ratio (i.e 40/60/20) or try this macronutrient calculator.

With an understanding of how nutrients work with the body, we can now use our knowledge to create a personalized breakdown of what, and how much, we should eat to meet our goals. A macronutrient ratio is a specific ratio (percentage) of calories as they relate to our macros (protein/carbs/fats). The following is an example of calorie distribution:

For example: Let's assume we have someone who weighs 150 lbs, eating 1600 calories/day we can solve for total caloric distribution. Because we know that we need to consume anywhere from 0.8g/lb - 1g/lb of bodyweight, we can figure out how many total calories should come from protein first:

0.8g/lb/day x 150 lb (bw) = 120g/day

120g/day x 4/cal/g = 480 cal/day (protein)

480/1600 = 0.3(100) = 30% protein

We now know that eating 0.8g/lb of bodyweight would account for a total of 30% of our target total caloric intake for the day. This means we have 70% of total daily calories remaining for fat & carbs. If our goal involves maintaining lean mass, we would want to have an even balance in calories between the two, making our ratio (30/45/45).

Now that we know our ratio, we need to find out how many calories remain for practical purpose:

70% / 2 = 45%

1600 x 45% = 720 cal

Let's solve for grams of carbs (g/cal) first:

720 cal/carbs / 4 cal/g/carb = 180 g/carbs

Let's solve for grams of fat (g/fat) next:

720 cal/fat / 9 cal/g/fat = 80 g/fat

So, no we know that for a person who weighs 150 lbs, wants to maintain weight, and is consuming a total caloric intake of 1600/cal per day, they would need to eat a distribution of 30/45/45 (protein/carbs/fat) which equates to 120 g of protein (or 480 calories), 180 grams of carbs (or 720 calories) and 80 grams of fat (or 720 calories).

You now know how to calculate a macronutrient breakdown using nothing but your goals, estimated caloric expenditure, and bodyweight. Now we know that not everyone feels confident enough with mathematics to figure all this out, so we made a macronutrient calculator to help you.


The Extra:

Account for activity using the

macronutrient calculator

macronutrient calculator

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