Macronutrients 101

How Protein, Fat, and Carbohydrates Fuel Your Body

Grilled meats and vegetables

Brian Leatart / Getty Images

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

Your body also requires micronutrients in smaller amounts, such as vitamins and minerals. But macronutrients provide your body with calories (energy) and the building blocks of cellular growth, immune function, and overall repair. It is important to balance macronutrients for optimum health and wellness.

The 3 Primary Macronutrients

Each of the three primary macronutrients affects the body in a different way. In order to understand how to balance your macro intake in your daily diet, it's important to learn the important role that each plays in the body.


Carbohydrates are the body's preferred source of fuel. It is easier for the body to convert carbohydrate into immediately usable energy than it is for the body to convert fat or protein into fuel. Your brain, your muscles, and your body's cells need carbohydrate to function.

When you consume carbohydrates, the food is converted into sugars that enter the bloodstream. Those sugars (glucose) are either used immediately for energy or stored in the body's cells for use at another time.

Carbohydrates provide the body with fuel. Carbs are broken down into sugar (glucose) in the body and either provide immediate energy or are stored for later use.

Carbohydrates can either be complex or simple.

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 quick and fleeting impact on blood sugar levels. Blood sugar (and energy) levels typically rise quickly then drop after consuming simple carbs.

Complex carbohydrates (polysaccharides and oligosaccharides) are made up of long strings of sugar units that take longer to break down for use in the body. Complex carbs have a more steady impact on blood glucose levels.

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

Examples of foods high in carbohydrates include starchy foods like grain products (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 45 to 65 percent of our daily caloric intake come from carbohydrate. However, some people follow lower carbohydrate diets to manage a medical condition or for weight loss.


Protein provides the body with building blocks (amino acids) for muscle and other important structures such as the brain, nervous system, blood, skin, and hair. Protein also serves as transport for 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—or building blocks—on its own. But there are 9 amino acids that you must consume in the daily diet because your body is unable to make them.

There are different types of protein that you might consume to get these amino acids. Complete proteins provide all of the amino acids that your body needs in appropriate amounts. Meat, poultry, and seafood products are the most commonly cited complete proteins. Eggs and milk are also examples of complete proteins.

Incomplete proteins provide some amino acids but not all of them. Many plant-based proteins are incomplete proteins and must be consumed together as complementary proteins in order to get all of the amino acids that the body needs. Nuts, seeds, and (most) grains are examples of incomplete proteins.

Requirements for protein vary. The USDA recommends that we consume anywhere from 10 to 30 percent of our daily calories from protein. Specific protein guidelines are based on age, gender, and activity level. And some people consume more protein to reach certain fitness or wellness goals.

Many Americans get more than enough protein from the foods they consume. However, protein supplements are also widely used, although not necessary in many cases.


While many people try to avoid fat in their diets, 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.

While fat is necessary for a healthy body, fat can also contribute to obesity. Fat provides more energy (9 calories per gram) than carbohydrate or protein (4 calories per gram). So this macronutrient must be consumed in moderation in order to maintain a healthy weight.

There are different types of fat that you might consume in your daily diet. Dietary fats might be saturated or unsaturated.

Saturated fats come mostly from meat and dairy sources. These fats are generally solid at room temperature and tend to be shelf-stable for a longer period of time.

Unsaturated fats include those that are monounsaturated or polyunsaturated. Unsaturated fats come from plant-sources and provide the body with certain health benefits. These fats are generally liquid even when refrigerated and have a shorter shelf life.

Studies have shown that when we replace saturated fats with poly or monounsaturated fats, we decrease our risk for certain diseases including heart disease, stroke, and type 2 diabetes.

Sources of Saturated Fats
  • Butter

  • Lard

  • Fatty meats

  • Cheese

  • Full fat dairy products

Sources of Unsaturated Fats
  • Nuts

  • Seeds

  • Plant-based oils, such as olive oil

  • Fatty seafood (salmon, tuna, etc.)

  • Avocado

Another type of fat, called trans fat, is slowly getting eliminated from foods. This type of fat starts as a polyunsaturated fat and is hydrogenated to become shelf-stable. These hydrogenated fats are often used in processed baked goods like crackers, cookies, and cakes. However, health experts have advised against consumption of trans fats so food manufacturers have begun removing them from foods.

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

How to Balance Macronutrients

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

The large range of percentages recommended for each macronutrient leaves room for experimentation. Everyone's body may function differently with various ratios.

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

One 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.

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

Macronutrient numbers provided by the USDA and other sources provide a guideline for recommended ranges. To find the right balance for you, use the My Plate icon along with recommendations from your healthcare provider and make adjustments as needed.

Tracking Macros vs. Tracking Calories

Some people—particularly athletes—track their macronutrient intake rather than their calorie intake in order to reach certain fitness or performance goals. Some people may also manage a medical condition by watching their macro intake. For example, those with type 2 diabetes often manage and limit their carbohydrate intake.

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

Why Track Calories?

If your goal is weight management, the success or failure of your program ultimately rests on your overall calorie intake. You won't lose weight unless you create a substantial calorie deficit on a regular basis. In order to maintain your weight, you will likely need to consume a modified version of your weight loss calorie goal.

For these reasons, many people who are trying to reach or maintain weight loss simply track calories. Calorie counts can easily be found on the Nutrition Facts label of any food and if it is not available there, most nutrition databases provide accurate numbers online or in smartphone apps.

Tracking calories is simple and requires little time or effort.

Why Track Macronutrients?

Even though tracking calories is easy (requiring you to manage just one number), some people may track macros instead. Tracking macronutrients is more complex as you need to set goals for three intake numbers instead of one. But some people, including those trying to reach fitness goals and those trying to lose weight, find these numbers helpful.

For example, people who are trying to lose weight may find that they can reach their calorie goal with greater ease if they consume more calories from protein. Protein generally provides greater satiety than carbohydrate and may help you eat less overall if you include it at every meal.

People who are managing heart disease or a related condition may track their intake of fat—particularly saturated fat, in order to reduce their risk for a cardiac incident.

And lastly, people who are trying to reach fitness goals may track their macros. For example, endurance runners may try to target a particular carb intake in order to be properly fueled for a race. And strength-trained athletes may watch their intake of protein in order to reach 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 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.

Popular apps include LoseIt, 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 of them provides a vital function. It is important to consume each of them in balance unless suggested otherwise by your healthcare provider.

Once you've learned how to balance your macros, learn how to make healthy choices within each group. Choose lean proteins, complex carbohydrates, and healthy fats to reach your fitness goals or maintain wellness.

Was this page helpful?
Article 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.
  • Dietary Guidelines 2015-2020. Appendix 7. Nutritional Goals for Age-Sex Groups Based on Dietary Reference Intakes and Dietary Guidelines Recommendations. Table A7-1.

  • Dietary Fats. Medline Plus. U.S. National Library of Medicine. March 2019

  • Total Carbohydrate Fact Sheet. U.S. Food and Drug Administration.

  • Protein Fact Sheet. U.S. Food and Drug Administration.

  • Total Fat Fact Sheet. U.S. Food and Drug Administration.

  • Carreiro, A. L., Dhillon, J., Gordon, S., Higgins, K. A., Jacobs, A. G., McArthur, B. M., … Mattes, R. D. (2016). The Macronutrients, Appetite, and Energy Intake. Annual Review of Nutrition36, 73–103. doi:10.1146/annurev-nutr-121415-112624

  • Liu, A. G., Ford, N. A., Hu, F. B., Zelman, K. M., Mozaffarian, D., & Kris-Etherton, P. M. (2017). A Healthy Approach to Dietary Fats: Understanding the Science and Taking Action to Reduce Consumer Confusion. Nutrition Journal16(1), 53. doi:10.1186/s12937-017-0271-4

  • Macronutrients: The Importance of Carbohydrate, Protein, and Fat. McKinley Health Center University of Illinois at Urbana-Champaign. 2014.