What are Macronutrients?

You’ve probably heard more than one fitness enthusiast talk about macronutrients, or macros for short.  It’s a word commonly tossed around gyms, health food shops, and podcasts.

Understanding what macronutrients are will help you grasp the processes that happen in your body every day and will help you to make smarter food choices to improve your health. 

We’ll dodge most of the science-speak and dive deep into the biochemistry in another section.

So what exactly is a macronutrient?

Macro means big, so we’re talking about types of nutrients that we eat in large amounts.  There are three macronutrient classifications.  They are proteins, fats, and carbohydrates.  They each behave differently when eaten, and they have different functions in the body.

Protein is the most vital, and it’s further broken down into individual amino acids during digestion.  Protein is the essential building block of all the tissues in the body, from bones to muscles to skin.  Protein is necessary for each of the chemical reactions in the body including hormone production, immune system function, and enzyme reactions.

You should aim to get protein at each meal, and if you snack you should include protein here too.  Protein is the most satiating macronutrient, which means it makes you feel full.

It’s hard to eat too much protein because of the strong signal your brain sends of Stop Eating when you’ve had enough.  Contrast that with the satiety of carbs or fat. 

Have you ever eaten a family sized bag of chips (carbs) and still wanted more food?  And I promise you I can eat a whole stick of butter (fat) and still be hungry.  That’s never happened for real.  I swear.

High protein foods include meats, poultry, fish, seafood, eggs, and dairy.  Nuts and seeds also contain good amounts of protein.  There are plenty of products on the market like protein powders, bars, and cookies, and we’ll get into reading the labels of these things in another section.

A good gauge of how much protein you should eat per serving is roughly the size of your palm, and you should have that much 3-4 times a day.  This is an easy measurement because it doesn’t require a scale or calculation, and it’s based on you, not a hypothetical person in a book.  Sure, you can drill down to precise grams if you start aiming for more hardcore goals.  To fit into real life though, aim for protein the size of your palm, 3-4 servings a day.

Next up is fats, and you need these in your diet too.  Fat is necessary for hormone balance, soft skin, brain function, energy production, and cell membrane integrity.

Learning to add healthy Fats into your diet is the most important component of a Low Carbohydrate Diet. After all, you have to replace the carbohydrates with something. 

There is a lot of belief still today that fat in the diet causes heart disease.  The Diet Heart Hypothesis, also called the lipid hypothesis of heart disease, gained popularity in the 1950’s and reached its peak in the 1980’s, where there was a surge in advertisement and products geared toward a low fat, especially low saturated fat way of eating.

The theory was that saturated fat in the diet was the cause of increased blood cholesterol and the formation of plaques in the artery walls that are closest to the heart.  Studies have shown that replacing saturated fat can indeed lower cholesterol to some extent, but this switch made no difference to heart disease risk, putting the connection between cholesterol and heart disease into serious question.

Here’s the kicker.  After all of the studies were analyzed that looked at replacing saturated fat with unsaturated fat, and reducing total fat in the diet, and replacing fats with carbohydrates, researchers found that those with the lowest saturated fat intake, and those with the lowest overall fat intake, and those who had higher carbohydrate intake, and those who had the lowest cholesterol levels had the HIGHEST risk of mortality.

Less saturated fat and less fat overall and more carbohydrates and less cholesterol meant earlier death.

This means that the people that ate more saturated fat and who had higher blood cholesterol lived the longest.

One more time, with feeling:  more saturated fat and more cholesterol means living longer.

After reexamining the data, the results of these studies were so clear that in 2015 the USDA completely revised its recommendations from the past 40 years, removing the limit on a recommended amount of fat in the diet.  Moreover, they added a recommendation to limit added sugars, which is a step in the right direction.  The previous four decades of focus on carbohydrates, like “healthy whole grains” and sweets, has caused a dramatic spike in the obesity epidemic and the chronic diseases that go along with it.  It’s heartening to see (pun intended) that changes are being made that can genuinely improve the health of millions of people. (1, 2, 3, 4, 5, 6)

The moral of the story?


Fat is fuel, plain and simple.  When you’re adjusted to this new way of eating, you might even consider it jet fuel because you can burn it more efficiently than carbs.  You can expect more physical energy and clearer thinking when you run on fats.

There are different types of fats, and some are better than others.  The less processed your fat source, the better. For example, butter, coconut oil, and bacon fat are pretty easy to get from their sources.

They’re saturated fats which tend to be healthier since they are stable at room temperature and when cooking at higher heat.  Monounsaturated fats like avocado oil, olive oil, and macadamia oil are best used unheated, like in salad dressings.

Polyunsaturated fats like Omega 3s and Omega 6s are healthful in small amounts.  They’re both necessary for great health.  The ideal ratio of these fats is 4 to 1.  Omega 6 fats tend to be higher in the diet, so for each 4 parts of these you want to get at least one part of Omega 3s.  This balance helps to manage inflammation, optimize brain health, and reduce the risk of chronic disease.  A typical western style diet often has a ratio of 12:1, and can be as high as 25:1, which is far out of balance.  This kind of diet is far too high in Omega 6 fats, and includes far to few Omega 3 fats.  A keto way of eating will naturally shift this balance to be more healthful, but it’s worth paying attention to.

Trans fats, such as in fried and processed foods are straight up poison that can cause rampant inflammation and disease so don’t eat them, okay?  In good news the FDA has started cracking down on the trans fats in food, so this could lead to healthier options on the shelves.

A serving of fat is about a tablespoon.  I’m not going to make you measure every time you use fat, that’s excessive, but please do take a look at a measuring spoon when you’re done reading so you can eyeball a little more accurately.  It should be roughly the size of your first thumb joint.

Fat makes food delicious so it’s easy to eat more than you need for your level of activity.

Use enough to cook your food or make just enough dressing.  Don’t eat it out of the jar with a spoon.  Again, I have never ever done this today.

Finally, carbohydrates, aka carbs.  You don’t need them.  I’m not just being irreverent here, this is the only macronutrient that you can eliminate from your diet and not suffer negative consequences.  Carbs have been a staple in our diets for centuries, ever since agriculture became a thing.  We’ll talk about why it’s a bigger problem now than it was back then another time.  For now, let’s focus on what they are and how to avoid them. (7, 8, 9, 10, 11, 12)

Carbohydrates, which are sugars and starches, break down into glucose through digestion to provide a very fast source of energy to your body.  Glucose stimulates the release of insulin, a hormone that allows substances to enter into cells.  You always have a little in your bloodstream and it’s necessary for health.

Constant or very high glucose loads lead to insulin measurements that look a lot like a roller coaster, and you feel like your energy is on one too.

Another problem with carbs is that since they’re broken down so easily (and you can overeat them so easily) that any excess carbs you eat get stored as fat.  Remember how insulin shuffles substances into cells?  That includes excess calories, where they stay until your cells are prompted to release and burn them for energy.  If you’ve tried to lose weight in the past, you know how challenging that can be.

You can find carbohydrates is many delicious foods, both processed and unprocessed.  Anything sweet or starchy (with some very specific exceptions we’ll get into later) is a carb.  Bread, pasta, rice, potatoes, candies, cakes, pastries, and ice cream are all primarily carbohydrate foods.  Fruit, honey, oatmeal, jam, and whole grains are carbs too.  No, I’m not trying to cut your heart out by listing all of your favorite foods.  There are alternative foods and some pretty neat recipes that fill in the blanks here so you won’t have to do without your favorites.

To be fair, you do need a minuscule amount of carbohydrate in your body, in the form of roughly 20 grams of blood glucose. 

Certain hormonal reactions and neurological processes absolutely require glucose for fuel.  There are two ways you can get this teeny weenie amount.  First, yeah, you eat it, but it’s the incidental carbohydrate present in other foods, like broccoli or almonds or dark chocolate.  Second, through a process called gluconeogenesis.  Science!  Gluconeogenesis is when glucose is created from other substances, usually protein, and preferably from food and not your own muscle mass.  (Hey look, another reason to eat plenty of protein!)  This happens only when your body needs glucose and it isn’t present in the diet.  Eating too much protein isn’t realistically a problem.

After you’ve adapted to using fat for fuel, you can plan keto breaks, or refeeds, where you have higher carb days.  Some people find that they need a carb boost periodically for better energy, consistent weight loss, or just because dammit you need the chocolate for your sanity.

You can plan a carb refeed once every 7-14 days.  You don’t have to, but if you feel like you need it, do it.  It won’t hurt your progress and you’ll still be getting the benefits of your lower carb diet.

Carb caveat: fiber isn’t counted in the carbs that are linked to weight gain and health risks even though it’s technically a carbohydrate.  This is because we can’t fully digest fiber.  Fiber helps to keep our digestive systems moving along smoothly, and it makes the probiotic bacteria in our guts happy.

Fiber doesn’t get fully digested, but it is essential in your diet.  Sure, there is fiber in the grains that you’re no longer eating.  There’s also a lot of fiber in most vegetables, like broccoli, brussels sprouts, mushrooms, and every sort of leafy green you can get your hands on.

Fiber is necessary for intestinal health, helps to balance blood glucose, and studies have shown that diets high in fiber reduce the risk of obesity, heart disease, stroke, and death. (13)

To review, the three macronutrient categories are proteins, fats, and carbohydrates, and your body uses them for different things.  If you change the balance of them, you can alter the way your body works, for better or for worse.  We can clearly see the worse in the obesity and health epidemics today, and you’re here because you’re ready to do better.

Drop your questions below and we’ll get back to you as soon as we’re done with this avocado that’s ripe only for the next 10 minutes.

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