Macronutrients 101

How Protein, Fat, and Carbohydrates Fuel Your Body

Meats and vegetables

Verywell / Alexandra Shytsman

Macronutrients (also known as macros) are nutrients that the body uses in relatively large amounts and therefore needs to receive daily. There are three macronutrients: proteins, carbohydrates, and fats.

Your body also requires micronutrients (such as vitamins and minerals) in smaller amounts, but the macronutrients provide your body with calories (energy) and the building blocks of cellular growth, immune function, and overall repair.

Here's what you need to know about macronutrients and why a balanced intake of these vital nutrients are necessary for optimum health and wellness.


The three primary macronutrients are carbohydrates, fat, and protein. Carbs fuel your body with immediate energy. Protein provides amino acids, which are essential for building muscle, skin, blood, and important structures of the brain and nervous system. And fat is vital for brain development, insulation, energy reserves, cell function, and protection of your organs. Learn more about each macronutrient below.


Carbohydrates are the body's preferred fuel source. Converting carbohydrates into immediately usable energy is easier for the body than converting fat or protein into fuel. Your brain, muscles, and cells all need carbohydrates to function.

When you consume carbohydrates, the food is converted into sugars that enter the bloodstream. These sugars (in the form of glucose) can be an immediate source of energy or stored in the body's cells to be used at another time.

Carbohydrates provide the body with fuel. The body breaks carbs down into sugar (glucose) which either provides immediate energy or gets stored for later use.

Carbohydrates can either be complex or simple:

  • Complex carbohydrates (polysaccharides and oligosaccharides) are made up of long strings of sugar units that take longer for the body to break down and use. Complex carbs have a more steady impact on blood glucose levels.
  • Simple carbohydrates (monosaccharides and disaccharides) are made up of either one or two sugar units and can be broken down fairly quickly in the body. Simple carbs have a fleeting impact on blood sugar levels. Some types of simple carbohydrates (when consumed in isolation), such as juice or sugary candy can cause blood sugar and energy to rise quickly and then drop shortly after.

In addition to providing fuel to the body, complex carbohydrates (particularly fiber) help the body maintain healthy digestive function and cholesterol levels.

Examples of foods that are high in carbohydrates include starchy foods like grain products (such as bread, cereal, and pasta), potatoes, and rice. Fruits, vegetables, and dairy products also provide carbohydrates.

Complex Carbs
  • Peas, beans, and other legumes

  • Whole grains

  • Breads and cereals

  • Rice

  • Starchy vegetables

  • Pasta

Simple Carbs
  • Table sugar

  • Honey

  • Maple and other syrups

  • Candy

  • Fruit juice, sweetened tea, and soda

  • Milk

The United States Department of Agriculture (USDA) suggests that carbohydrates make up 45% to 65% of our daily caloric intake. However, some people follow lower carbohydrate diets to manage a medical condition or for weight loss.

The department's Dietary Guidelines for Americans 2020–2025 also recommend that sugar intake be limited to less than 10% of daily calories while the Dietary Guidelines Advisory Committee and the American Heart Association (AHA) recommend an even lower limit of less than 6%.


Protein provides the body with amino acids, which are the building blocks for muscle and other important structures such as the brain, nervous system, blood, skin, and hair. Protein also transports oxygen and other important nutrients. In the absence of glucose or carbohydrate, the body can reverse-process protein (a conversion called gluconeogenesis) to use as energy.

Your body makes 11 amino acids on its own. There are 9 amino acids that your body cannot make (known as "essential amino acids"), which means you need to consume them through your diet.

You can consume different types of protein to get these amino acids.

  • Complete proteins provide all of the amino acids that your body needs in appropriate amounts. The most common sources of complete protein are meat, poultry, seafood, eggs and milk, quinoa, and edamame.
  • Incomplete proteins provide some, but not all, of the amino acids you need. Many plant-based proteins are incomplete proteins. However, when they are consumed together as complementary proteins, you can get all the amino acids that your body needs. Nuts, seeds, and (most) grains are examples of incomplete proteins. You can consume these foods separately or together throughout the day to get the essential amino acids you need.
Complete Proteins
  • Poultry and eggs

  • Beef and pork

  • Salmon

  • Soy

  • Quinoa

Incomplete Proteins
  • Lentils

  • Nuts

  • Beans

  • Whole grains

  • Vegetables

The daily requirements for protein vary. The USDA recommends that we consume anywhere from 10% to 35% of our daily calories from protein sources. More specific protein guidelines are based on age, sex, and activity level. Some people will consume more protein to reach certain fitness or wellness goals.

Protein Supplements

Many Americans get more than enough protein from the food they eat. While protein supplements are popular and widely used, in many cases, they are unnecessary.


People might try to avoid fat in their diets, but dietary fat plays an important role in the body. Fat provides an important source of energy in times of starvation or caloric deprivation. It is also necessary for insulation, proper cell function, and protection of our vital organs.

Excessive calorie intake in the form of saturated and trans fat, however, has been linked to a variety of diseases, including heart disease and diabetes. When meal planning, it is important to understand that fat contains double the calories per gram as protein or carbohydrates.

There are different types of fat that can be part of your daily diet. Specifically, dietary fats might be saturated or unsaturated:

  • Saturated fats mostly come from meat and dairy sources. These fats are generally solid at room temperature and tend to be shelf-stable for a long time. However, when it comes to cardiovascular risk, saturated fat should be avoided from meats versus dairy. Full-fat dairy products either has a neutral or beneficial effect on cardiovascular health.
  • Unsaturated fats include two other types of fats: monounsaturated and polyunsaturated fats. Unsaturated fats come from plant-sources and fortified foods such as eggs and dairy, as well as fish, seaweed, and grass-fed animal products. They provide the body with many health benefits. These fats are generally liquid even when refrigerated and have a shorter shelf life than saturated fats.

When saturated fats in a person's diet are replaced with poly or monounsaturated fats, it can decrease their risk of certain diseases including heart disease, stroke, and type 2 diabetes.

Saturated Fats
  • Butter

  • Lard

  • Fatty meats

  • Cheese

  • Full fat dairy products

Unsaturated Fats
  • Nuts

  • Seeds

  • Plant-based oils, such as olive oil

  • Fatty seafood (e.g., salmon and tuna)

  • Avocado

Another type of fat, called trans fat, is slowly getting eliminated from foods. Trans fat is a polyunsaturated fat that is processed to become shelf-stable. Processed foods like crackers, cookies, cakes, and other baked goods typically contain these hydrogenated fats.

Most dietary guidelines suggest that roughly 20% to 35% of your daily calories should come from fats. However, no more than 10% of your daily calories should come from saturated fats.

Health experts have advised against the consumption of trans fats. As a result, food manufacturers have started to remove them from their products. Certain foods have trace amounts of natural trans fat, such meat and dairy products, but there hasn't been substantial evidence to suggest whether or not these have the same effects are commercially made trans fats.

How to Balance Macronutrients

It is important to include each macronutrient in your daily diet. This will be easier if you build each meal around a combination of protein, carbs, and healthy fats. That said, finding the exact balance of macros that's right for you can be tricky.

The large range of percentages recommended for each macronutrient leaves room for experimentation. Everyone's body functions differently when various ratios are consumed.

An easy way to plan your meals is to use the USDA's MyPlate system which simply encourages you to use a divided plate icon to plan your meals. Roughly one-quarter of the plate is designated for fruits, vegetables, grains, and proteins. There is also a small icon for dairy.

There is a similar system called the Healthy Eating Plate that is provided by Harvard Health. Each plate image can serve as a reminder to get your nutrition from different sources to ensure that your macro and micronutrient needs are met.

When you first begin to balance your macros, the goal is to keep each range within its boundaries, but ensure you get enough of each nutrient.

Tracking Macros vs. Tracking Calories

Some people—particularly athletes—track their macronutrient intake rather than their calorie intake because they are trying to reach certain fitness or performance goals. A person might also manage a medical condition by watching their macro intake. For example, people with type 2 diabetes often count carbs to manage and limit intake.

There are pros and cons to tracking calories and pros and cons to tracking macros; the best method for you will depend on your goals.

Why Track Calories?

If your goal is weight management, the success or failure of your program will ultimately rest on your overall calorie intake. You won't lose weight unless you create a calorie deficit on a regular basis, meaning you are taking in fewer calories than you burn.

Some people find calorie counting to be a good motivator in losing weight. There are many factors that affect weight loss, calories being one of them. Creating a calorie deficit can result in weight loss but this concept complicated and dynamic.

People who are trying to reach or maintain weight loss often choose to track the calories they consume. The calorie counts for most foods and beverages can be found directly on the Nutrition Facts label. If it's not available there, there are nutrition databases that provide accurate numbers online or even in smartphone apps.

Why Track Macronutrients?

Tracking calories might appear to be easier since you are only calculating one number, but some people choose to track macronutrients instead to reach specific goals. Tracking macronutrients is more complex because you need to set goals for three intake numbers instead of just one. For people trying to reach fitness goals or lose weight, these numbers can be helpful.

For example, people who are trying to lose weight might discover that they can reach their calorie goal more easily if they get more of their daily calories from protein. When included at every meal, protein might help you eat less because it generally provides greater satiety than carbohydrates.

People who are managing heart disease or a related condition might track their intake of fat—particularly saturated fat—to reduce their risk for a cardiac event.

People who are trying to reach fitness goals often track their macros. For example, endurance runners might target a particular carb intake to ensure that they are properly fueled for a race. Strength-trained athletes might watch their intake of protein to help them reach their performance goals.

Tools and Tips to Track Macros

If you choose to track your macros, there are different methods you might use to manage your intake. One of the easiest ways is to use a smartphone app.

Many health and wellness apps provide calorie and macro data for countless foods. These apps help you to input each food you consume and then provide updated charts and other graphics to let you see where you're at throughout the day. Examples of popular apps include LoseIt, MyMacros+, and MyFitnessPal, and Fitbit.

Another method is to use the old-fashioned pen and paper approach. You can either plan meals in advance according to the macro balance that you require, or you can use online resources or apps to get your numbers and keep them in a notebook.

A Word From Verywell

Each macronutrient provides an important role in the body. While some trendy diets severely restrict or even eliminate some macros, each is essential to your body's ability to function optimally. You need to consume each of them in balance (unless your healthcare provider has advised you otherwise—for example, because you are managing a health condition).

Once you've figured out how to balance your macros, you can learn to make healthy choices within each group. To reach your fitness goals and maintain your wellness, choose lean proteins, complex carbohydrates, and healthy fats.

It is important to note, however, that intensive counting of macros may be contraindicated in people with a history of eating disorders. This type of eating approach also limits a person's ability to listen to their internal hunger cues, so it's best to consult your healthcare provider or a registered dietitian before making any significant changes to your diet.

Frequently Asked Questions

  • What is the role of macronutrients?

    Macronutrients provide all of the fuel that makes your body work. Your body depends on macronutrients as its only sources of energy. They also contribute to building cells

  • What are the correct macros for weight loss?

    When people count macros for intentional weight loss, the idea is to hit a target number of grams of each macronutrient each day. The amount of protein, fat, and carbohydrates needed to lose weight varies depending on starting weight, how active a person is, and other complex factors. Because it requires paying close attention to food intake and counting grams of the different macros, it is not recommended for people with a history of disordered eating.

  • What foods are high in macros?

    Different foods are good sources for different macronutrients. Whole grains, rice, and pasta are good sources of complex carbohydrates. Chicken, fish, and quinoa provide complete proteins. Nuts, cooking oils, and avocado are great foods to provide unsaturated fat.

5 Sources
Verywell Fit uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. U.S. Department of Agriculture. Dietary Guidelines for Americans 2020-2025.

  2. Harvard School of Public Health. Types of fat.

  3. Sendra E. Dairy fat and cardiovascular healthFoods. 2020;9(6):838. doi:10.3390/foods9060838

  4. American Heart Association. Fish and omega-3 fatty acids.

  5. American Heart Association. Trans fats.

Additional Reading

By Laura Dolson
Laura Dolson is a health and food writer who develops low-carb and gluten-free recipes for home cooks.