Macronutrients, or “macros,” are nutrients your body needs in large amounts to function optimally. Carbs, protein, and fat are the three main macros.

Macronutrients are a group of nutrients that provide your body with energy and the components it needs to maintain its structure and functions.

Macronutrients include carbohydrates, protein, and fat. They’re needed in relatively larger amounts than other nutrients, hence the term “macro.” Although there are recommended ranges for macronutrient intake, your needs vary based on your personal circumstances.

This article reviews the main macronutrients, food sources, functions, and how to assess your macro needs.

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Macronutrients are nutrients that your body needs in large amounts to function optimally.

The three main macronutrients are carbohydrates, protein, and fat. They’re considered essential nutrients, meaning your body either cannot make them or cannot make enough of them (1).

For example, proteins provide essential amino acids, while fats contain essential fatty acids. Your body utilizes these components for specific functions (2).

Macronutrients also contain energy in the form of calories. Carbs are the main energy source, but your body can use other macronutrients for energy if needed (3).

The calorie content of each macronutrient is (4):

  • Carbs: 4 calories per gram
  • Protein: 4 calories per gram
  • Fat: 9 calories per gram

Macronutrients include carbs, protein, and fat. They provide energy in the form of calories and are needed to maintain your body’s functions and structure.

You can obtain macronutrients from the foods you eat. It’s important to eat a variety of foods to get enough of each macronutrient.

Most foods contain a combination of carbs, protein, and fat.

Some foods are high in one specific macronutrient, while other foods contain high amounts of two nutrients and fall into two macronutrient groups.

Sources of carbs include:

  • Whole grains: brown rice, oats, farro, and barley
  • Vegetables: peas, potatoes, corn, and other starchy veggies
  • Fruits: mangoes, bananas, figs, and apples
  • Beans and legumes: black beans, lentils, and chickpeas
  • Dairy products: milk and yogurt

Sources of protein include:

  • Poultry: chicken and turkey
  • Eggs: particularly egg whites
  • Red meat: beef, lamb, and pork
  • Seafood: salmon, shrimp, and cod
  • Dairy products: milk, yogurt, and cheese
  • Beans and legumes: black beans, lentils, and chickpeas
  • Nuts and seeds: almonds and pumpkin seeds
  • Soy products: tofu, edamame, and tempeh

Sources of fat include:

  • Extra virgin olive oil
  • Coconut: fresh, dried, and coconut oil
  • Avocados: fresh and avocado oil
  • Nuts and seeds: almonds and pumpkin seeds
  • Fatty fish: salmon and herring
  • Dairy products: full fat yogurt and cheese

Carbs are primarily found in grains, fruits, beans, and starchy vegetables. Protein-rich foods include eggs, meat, fish, and soy products, while high fat foods include avocados, nuts, seeds, cooking oils, and fatty fish.

Each macronutrient has specific functions in your body.

During digestion, they’re broken down into smaller parts. These parts are then used for bodily functions like energy production, muscle building, and giving structure to cells.


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 (3, 5).

Some of the main functions of carbs include (3, 5):

  • Instant energy. Glucose is the preferred energy source for your brain, central nervous system, and red blood cells.
  • Storing energy. Glucose is stored as glycogen in your muscles and liver for later use when you need energy, for example after a longer period of fasting.
  • Digestion. Fiber promotes healthy bowel movements.
  • Helps you feel full. Fiber fills you up after eating and keeps you feeling full for longer.


Proteins are digested into amino acids. Twenty amino acids have important functions in your body, 9 of which are essential and must be obtained from foods (5, 6).

Some of the main uses of amino acids from protein include (5, 6):

  • Building and repairing. Amino acids help create new proteins within your body. They’re also used to build and repair tissues and muscles.
  • Providing structure. Amino acids provide structure to your body’s cell membranes, organs, hair, skin, and nails.
  • pH balance. Amino acids help maintain a proper acid-base balance within your body.
  • Creating enzymes and hormones. Without the right amino acids, your body cannot create enzymes and hormones.


Fats are broken down into fatty acids and glycerol (5, 7).

Some of the main functions of lipids, or fats, include (5, 7):

  • Cell membrane health. Lipids are an essential component of cell membranes.
  • Storing energy. Fat stored around your body serves as an energy reserve that can be used during periods during which you eat fewer calories than you burn.
  • Transport and absorption. Lipids help transport and promote the absorption of the fat-soluble vitamins K, E, D, and A.
  • Insulation. Fat insulates and protects your organs.

During digestion, macronutrients are broken down into smaller parts that are used for specific functions. Carbs are the main energy source, proteins help build and repair tissues, and fats insulate organs and make up cell membranes.

Macronutrients are different from micronutrients, which include vitamins and minerals.

First, macronutrients are needed in relatively larger amounts than micronutrients. However, that doesn’t mean that micronutrients are less important.

Micronutrients serve different roles in your body than macronutrients. There are 13 essential vitamins and 13 essential minerals, each of which has specific, sometimes overlapping functions.

As a reminder, essential means that you have to get those nutrients from your diet. Some vitamins — D, K, B12, and biotin — can be produced by your body, but not always in adequate amounts.

Micronutrients support growth, brain development, immune function, and energy metabolism (8).

While macronutrients provide energy and are the building blocks of your body’s structure and functions, micronutrients don’t contain calories. Instead, they’re vital for extracting energy from food and facilitating most bodily processes (8).


Micronutrients are different than macronutrients in that they’re needed in smaller amounts, don’t provide calories, and have different functions.

Each macronutrient is incredibly important for your body to function optimally. It’s crucial that you get enough carbs, protein, and fat by eating a balanced diet comprising a variety of foods.

Specifically, the United States Department of Agriculture (USDA) Dietary Guidelines recommend these Acceptable Macronutrient Distribution Ranges (AMDR) for adults (9):

  • Carbs: 45–65% of your daily calories
  • Protein: 10–35% of your daily calories
  • Fat: 20–35% of your daily calories

The guidelines also recommend that adults get at least 130 grams of carbs per day. This is the Recommended Dietary Allowance (RDA) and considered the amount necessary to provide your brain with enough glucose (9).

If there isn’t enough glucose available — which can happen if you’re following a strict keto diet or have issues regulating your insulin levels due to conditions like diabetes — your body is able to get energy by breaking down fat and protein.

When it comes to protein, the RDA for adults is at least 0.36 grams per pound (0.8 grams per kg) of body weight (10).

Keep in mind, though, that the appropriate amount of macronutrients for each person varies based on their age, activity levels, sex, and other circumstances.

For example, children and adolescents may need more calories from fat than adults do for proper brain development (9).

Older adults, on the other hand, need more protein to preserve muscle mass. Many experts recommend a protein intake of at least 0.45–0.54 grams per pound (1.0–1.2 grams per kg) for adults over the age of 65 (11).

Athletes and highly active people often need more carbs and protein than those who are less active. They should aim for the higher end of the recommended ranges. Extra protein supports muscle building after exercise, while carbs provide calories to replenish energy stores.

If you’re trying to lose weight, you might benefit from eating slightly below the recommended range of calories from carbs and above the range recommended for protein. Extra protein can help you feel full, while fewer carbs can promote a calorie deficit (12).


It’s recommended that you get 45–65% of your calories from carbs, 10–35% from protein, and 20–35% from fat. However, personal needs vary based on activity level, age, and other factors.

Counting macros is an increasingly popular tactic for people interested in losing weight. Some athletes or individuals who need specific amounts of a certain macro, such as protein for muscle building, also use this strategy.

It usually involves coming up with a goal percentage of calories from each macro group and planning your meals accordingly.

While macro counting can be an effective way for some people to reach their goals, it’s not necessary for everyone. In fact, if you eat a well-balanced diet with sources of each macronutrient, you likely meet the recommended intakes.

For example, simply building a balanced plate at each meal is a great way to ensure that you get enough carbs, proteins, and fats.

A rule of thumb is to fill about half of your plate with non-starchy vegetables, a quarter with high fiber carbs like fruit or whole grains, and the last quarter with a source of protein. Also, prioritize using healthy fats when cooking.

If you’re interested in further assessing your macronutrient intake, consider working with a registered dietitian to help you figure out and meet your needs.

Remember, the quality of the macros in your diet is more important than meeting a set amount every day.

For example, if you eat sugary treats and refined carbs to meet your daily carb goal, you won’t get nearly as many nutrients and fiber as you would by eating fruits, veggies, and whole grains.


Setting a macro goal and tracking how many macros you eat is a popular tactic for weight loss and muscle building. However, it’s not necessary for everyone. Eating a balanced diet with sources of each macronutrient will help you meet your needs.

Macronutrients include carbs, protein, and fat. They provide energy and support bodily functions and structure.

Current guidelines recommend that you get 45–65% of your daily calories from carbs, 10–35% from protein, and 20–35% from fat. However, individual needs vary.

To ensure you get enough macronutrients from food, eat a balanced diet with sources of carbs, protein, and fat at every meal.

Just one thing

Try this today: Looking to increase your intake of one of the macronutrients? Choose a food from the lists in this article — like brown rice for carbs, eggs for protein, or avocado for fat — and add it to your next meal!

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