Protein is one of three macronutrients and an important part of the diet. It is necessary to build strong muscles and produce certain hormones and enzymes. The body does not store protein, so it is important that people consume enough based on their age, health, sex, and activity level.

The recommended daily allowance (RDA) of protein for adults over 19 is 10-35% of daily calories. Very active people will need more protein in their diet to aid muscle repair and regeneration.

This article will explore what protein is, where it comes from, and how much the body needs. It will also explain how to calculate protein intake and whether it can help build muscle and aid weight loss.

A person drinking a protein shakeShare on Pinterest
VioletaStoimenova/Getty Images

Protein is one of the three macronutrients that provide us with energy. The other two macronutrients are carbohydrates and fat.

Proteins are made of amino acids, which link together in different combinations to create new proteins that help build muscles and bones. Proteins also create energy and produce enzymes and hormones.

The body produces 11 amino acids, known as non-essential amino acids. There are nine amino acids that the body cannot produce, known as essential amino acids that it must get from food instead.

‘Complete’ proteins are a good source of essential amino acids.

Learn more about macronutrients here.

Protein comes from animal and plant sources.

Animal sources, including chicken, beef, fish, or dairy products, contain all the essential amino acids and are high quality or complete protein sources.

Plant proteins, including beans, lentils, and whole grains, are incomplete proteins. Although they may not contain all the amino acids, they are still valuable protein sources.

Soy products derive from soya beans. They include edamame, meat alternatives, and tofu and contain essential amino acids, making them high quality, complete protein sources.

Learn the difference between plant and animal protein here.

According to the Dietary Guidelines for Americans 2020-2025, adults over 19 years should get 10-35% of their total daily calorie intake from high quality protein sources. Children ages 4–18 should consume 10-30% of their total calorie intake as protein.

One gram (g) of protein contains around 4 calories. A person who eats 2,000 calories daily and gets 20% of their calories from protein would consume 100 g of protein, totaling 400 calories.

Learn what to eat on a high protein diet here.

How to calculate protein intake

Using an online calculator, such as the one provided by the U.S. Department of Agriculture, may help people establish protein requirements.

Alternatively, the following calculation can provide the proper target for protein consumption in either grams or calories.

  • First, it’s important to know how many calories a person is likely to consume per day. An example is 2,300 calories.
  • A person should choose the percentage of the diet that will be protein. In this example, it will be 20%.
  • Multiply the total calories by the percentage of protein to get the number of calories from protein. 2300 x .20 = 460.
  • Divide the calories from protein by 4 to get the total grams of protein. 460 / 4 = 115.

Using this example, a person consuming 2,300 calories per day, aiming for 20% of their calories to come from protein, will need to consume 115 g of protein per day.

Learn more about calculating your protein requirements here.

Including protein as part of a balanced diet has been proven to assist with weight loss.

Of the three macronutrients, protein is the most satiating. Studies have shown that it provides a feeling of fullness for longer than carbohydrates or fats.

Several meta-analyses of studies showed increased weight loss, fat mass loss, and preservation of lean mass following high protein, calorie-restriction diets versus low protein, calorie restriction diets. Participants in these studies also had lower blood pressure, triglycerides, and reduced waist circumference overall when on the high protein diet.

Learn more about high protein foods and weight loss here.

High quality protein combined with exercise can help build muscle. Eating within 30–60 minutes of finishing exercise may be the most beneficial for building muscle. During this time, skeletal muscles make better use of nutrients in food than they do 3 hours after exercising.

The current recommended daily allowance (RDA) for protein is set at a level that prevents muscle loss and provides the minimum required amino acids. Individuals seeking to gain muscle should be eating more than the RDA.

Active individuals may eat up to 2 g per kilogram (kg) body weight of protein per day. The most active individuals may go as high as 3.5 g per kg body weight. Eating high protein levels for long periods may cause digestive, renal, and vascular problems.

Learn more about eating protein to build muscle here.

The RDA of protein for females ages 19-50 who are pregnant is still 10-35% of total daily caloric intake. But since pregnant people need extra calories during the second and third trimesters of pregnancy, the amount of protein they need to eat will be higher.

For teens under 18 who are pregnant, the RDA is 10-30% of total daily caloric intake from high quality protein sources.

Learn about what to eat during pregnancy here.

Eating more than 2g of protein per kg of body weight over a long period may cause digestive, vascular, and renal problems, including kidney stones.

High protein diets that are high in fat may also put an individual at risk for heart disease, high cholesterol, colon cancer, or other health problems.

Find out how much protein is too much here.

The proper amount of protein is important for maintaining balance in the body and rebuilding muscles and bones.

Protein can come from many sources, but only protein from animal sources or soy contains all the essential amino acids the body needs in a single food item. Combining incomplete protein sources makes it possible to get all of the essential amino acids a person needs.

A person should aim to get 10-35% of their total daily calories from protein unless they are very active or seek to build muscle. In this case, calculate 2-3.5g per kg of body weight of protein per day.

A person can talk with a dietitian or nutritionist to discuss their optimal protein intake.