Proteins are responsible for the growth and repair of the body's tissues. They also play an essential role in the production of hormones, enzymes, and red blood cells.
Each protein is made up of smaller building blocks called amino acids. Because the body cannot store amino acids, it must get a regular supply from the diet.
In the United States, people get most of their protein from animal sources, such as meat, fish, and eggs.
People following a vegan diet must, therefore, ensure that they eat enough plant-based protein to meet their dietary requirements.
The U.S. Department of Agriculture provide an online calculator that can estimate a person's recommended daily intake of protein and other nutrients.
This article describes seven ways to add protein to the diet and gives tips on getting the most benefit from this nutrient.
Different foods contain different combinations and amounts of essential amino acids (EAAs).
Compared with animal proteins, plant proteins tend to lack the full range of EAAs.
People following a strict vegan diet should, therefore, consume a variety of plant proteins in order to meet their EAA requirements.
Some of the best sources of plant protein include:
Legumes, also known as pulses, are the seeds or fruits of plants belonging to the Fabaceae family. Some common examples of legumes are peas and beans.
Legumes are a good source of protein for vegetarians and vegans. Examples of common legumes and their protein contents in grams (g) are listed below.
|Legume||Protein content per cup|
|cooked peas||5.23 g|
|cooked broad beans (fava beans)||12.9 g|
|cooked navy beans||15 g|
|cooked black beans||15.2 g|
|cooked pinto beans||15.4 g|
|cooked kidney beans||16.2 g|
|raw edamame beans||13.2 g|
|cooked lentils||17.9 g|
|cooked soybeans||31.3 g|
Chickpeas and hummus
Chickpeas, also called garbanzo beans, are among the most versatile legumes. People can buy them dried, precooked and canned, or ground into a flour.
Chickpeas are the main ingredient of hummus, and 1 tablespoon of hummus contains around 1.17 g of protein. Try combining this dip with carrot, celery, or cucumber slices for a quick and healthful snack.
Nuts and nut butters
Some common examples include:
|Raw nuts||Protein content per 100 g|
Nut butters are another option for people wishing to increase their intake of plant proteins.
For a quick and nutritious snack, try spreading one of these nut butters onto slices of fresh apple:
|Nut butter||Protein content per tablespoon|
|peanut (chunky)||3.85 g|
Chia seeds are the tiny black seeds of the Salvia hispanica plant, which is native to Central and South America. A single ounce of chia seeds provides 4.69 g of protein.
Try sprinkling chia seeds on breakfast cereals or adding them to a smoothie.
Oats contain the most protein of all the grains, with 1 cup providing 10.7 g of protein.
Beyond oatmeal, a person can use oats to make granolas and chewy bars. For extra protein, try adding other high-protein foods, such as nuts and seeds, and serving with yogurt or milk.
Quinoa is a seed harvested from the goosefoot plant. Quinoa is not technically a cereal and is suitable for people following a gluten-free diet.
Some people enjoy quinoa porridge in the mornings or adding the cooked seeds to salads and soups.
Also, according to a 2015 review, consumption of milk and yogurt could prevent overeating and assist weight loss. These products increase the concentrations of the hormones glucagon-like peptide-1 and peptide YY, which signal to the brain that the stomach is full.
However, it is worth noting that some of the researchers involved in the review received funding from dairy companies.
Some popular dairy products and their protein contents include:
|Dairy product||Protein content per cup|
|whole milk||7.69 g|
|skimmed milk||8.26 g|
|plain yogurt (whole milk)||8.5 g|
|low-fat plain yogurt||12.9 g|
|plain yogurt (skimmed milk)||14 g|
Cheese is another protein-rich dairy product:
|Cheese||Protein content per ounce|
|feta cheese||4.03 g|
|mozzarella (whole milk)||6.28 g|
|goat's cheese (hard)||8.65 g|
Around 46% of the total protein consumed in the U.S. comes from animal sources, such as meat, fish, and eggs.
Although meat is an excellent source of protein, it often contains high levels of saturated fats. These fats can raise levels of "bad" cholesterol in the blood, increasing a person's risk of heart disease.
To maintain healthy cholesterol levels, opt for poultry over red meat. A portion of skinless roasted chicken weighing 100 g contains 6.63 g of fat and 25.01 g of protein.
Fish is an excellent source of protein. It also contains high levels of EFAs, which have anti-inflammatory properties and help increase levels of "good" cholesterol in the blood.
Tuna fish is particularly rich in protein. A standard half-fillet serving of skipjack tuna provides 43.6 g.
Like fish, eggs are a good source of protein and EFAs. One medium egg provides 5.53 g of protein.
Protein powders have become a popular nutritional supplement for athletes and others who are looking to build muscle.
According to the Academy of Nutrition and Dietetics, most people, including athletes, can get all the protein that they need from food alone.
However, supplements are a quick and convenient option that can be useful for people who struggle to get enough protein from their diet.
When choosing a powder, it is important to consider its biological value (BV) score. The BV score indicates how effectively the body is able to make use of the protein in a food. A score of 100 indicates that the body can make use of all of the available protein.
Below, learn more about the contents and BV scores of various protein powders:
- Whey: This is one of two proteins derived from milk. Whey contains all the EAAs and has a BV of 104, making it an excellent source of usable protein.
- Casein: This is a slow-digesting protein derived from milk. Like whey, it contains all the EAAs, but it has a lower BV of 77.
- Soy: This represents a good vegan alternative to whey and casein proteins. It has a BV of 74, which is lower than the scores of both dairy proteins, but it contains all of the EAAs.
Protein shakes are a fast and convenient way to get more protein into the diet. To make a protein shake, blend fruits and 100% juice, milk, or water, then add a scoop of protein powder.
As an alternative to protein powder, a person could use high-protein foods such as peanut butter, chia seeds, or Greek yogurt in their shakes.
Having a protein shake for breakfast may relieve hunger and help prevent midmorning snacking.
A protein shake can also be a handy snack for the gym, and some experts suggest that consuming 20–25 g of protein immediately after exercise helps maximize muscle growth and repair.
Other research indicates that ingesting 20–40 g of protein every 3–4 hours throughout the day may be the best way to improve muscle growth and repair.
Overall, the most important thing is to meet daily protein requirements.
In this study, participants ate two identical meals on two separate days but changed the order in which they ate the proteins and carbs.
The researchers found that the participants' glucose and post-meal insulin levels were lower when they had eaten the proteins first.
Research shows that protein has a satiating effect on appetite, helping people to feel fuller for longer. This is, in part, because protein decreases levels of the hunger hormone ghrelin.
A 2015 review found that consuming 25–30 g of protein at every meal can help regulate the appetite and facilitate weight management.
Protein is an essential nutrient that performs a number of important roles in the body.
People should consume protein from a variety of sources to ensure that they get the right balance of EAAs.
Other factors, such as when a person eats protein, may help determine its effects on the body.