What Are Macronutrients?

Macronutrients are the largest class of nutrients the body requires and include protein, carbohydrates, and fats. If you’ve heard anyone talking about “macros,” they’re referring to these major nutrients. The amounts and ratio of macronutrients a person needs every day vary by age, lifestyle (sedentary, active, or very active), gender, health status, and health goals.

The USDA provides general recommendations for how Americans should allocate calories per macronutrient.[1] The nutrition facts label included on food packaging echoes these ratios and is based on a 2,000 calorie diet for the average American, including children and adults. Many diets try to optimize macronutrient ratios to produce certain results, like consuming protein (along with weight training) to gain muscle mass, or consuming fewer carbohydrates to help lose weight.

What Are Carbohydrates?
Carbohydrates include starches, sugars, and fiber. Carbohydrates contain four calories (kcal) per gram. Your body uses carbohydrates to fuel your body. Carbohydrates come in two forms: complex and simple. Simple carbohydrates include sugars like table sugar and high fructose corn syrup. Technically, honey and maple syrup also fall into this category. Complex carbohydrates are usually only described as starches that contain fiber, but this simplistic definition includes foods like whole wheat pasta and white potatoes.

How Many Carbohydrates Do You Need?
According to the United States Department of Agriculture (USDA), Americans should get between 45-65% of their daily calories from carbohydrates.[1]

Humans don’t produce the necessary enzymes to digest fiber, but it’s nonetheless required by the body. Your microbiota breaks down fiber by fermenting it and using it as their energy source. Your health relies on a balanced, well-nourished microbial gut community for many different functions, so make sure you get plenty of fiber-rich foods in your diet every day.

Sources of Carbohydrates
The best carbohydrates are micronutrient-dense whole foods that contain sugars or starches along with fiber. This definition leaves no room for confusion about whole fruit, which is considered a simple carbohydrate under some definitions. Fruit is an essential part of a healthy diet and 76% of Americans don’t eat enough.[2] Other excellent sources of carbohydrates include winter squash, beans, and ancient grains like quinoa.

What Is Protein?
Protein is the building block responsible for the growth and maintenance of your eyes, skin, hair, nails, organs, and muscle tissue. During digestion, protein is broken down into smaller chains called peptides and individual units called amino acids for absorption. Of the 22 amino acids, nine are essential to humans. These include histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine.[3] Histidine is unique in that it’s only required during infancy.

Proteins do a lot of work throughout the body. They embed themselves in your cells to regulate what goes in and out. They even envelop and transport some molecules to other locations in the body. Enzymes that catalyze the various chemical reactions in your body are made of folded chains of amino acids. The body creates hormones like leptin, immune proteins like interferon, and antibodies using amino acids.

How Much Protein Do You Need?
The USDA recommends that Americans get 5-35% of their calories from protein. This range is set to cover 97-98% of the population, and your needs may vary based on age and health status.[1] Protein, like carbohydrates, provides four calories (kcal) of energy per gram.

Sources of Protein
Whole, nutrient-dense foods are the best sources of protein. Notice I did not say they are the most concentrated sources of protein. So-called “high-quality” sources are very concentrated sources of peptides that share similar amino acid ratios with humans.