How much protein does a person need?
Is an important part of every diet. The amount of protein an individual needs depends on their age and sex.
Is a part of every cell in the body. It helps the body to build and repair cells and tissues. Protein is a major component of the skin, muscle, bone, organs, hair, and nails.
According to the Food and Drug Administration (FDA), most people in the United States get enough protein from their diets to meet their needs.
This article looks at protein, its function, sources, and how much protein different groups of people need each day.
Is one of three macronutrients, which are nutrients the body needs in larger amounts. The other macronutrients are fat and carbohydrates.
Protein is made up of long chains of amino acids. There are 20 amino acids. The specific order of amino acids determines the structure and function of each protein.
The 20 amino acids that the body uses to create protein are:
- aspartic acid
- glutamic acid
There are nine essential amino acids that the human body does not synthesize, so they must come from the diet.
Proteins may be either complete or incomplete. Complete proteins are proteins that contain all essential amino acids. Animal products, soy, and quinoa are complete proteins.
Incomplete proteins are proteins that do not contain all essential amino acids. Most plant foods are incomplete proteins, including beans, nuts, and grains.
People can combine incomplete sources to create a meal that provides all essential amino acids. Examples include rice and beans, or peanut butter on whole wheat bread.
What does do in the body?
Is present in every body cell, and an adequate intake is important for keeping the muscles, bones, and tissues healthy.
It plays a role in many bodily processes, including:
- blood clotting
- fluid balance
- immune system responses
Is important for growth and development, especially during
childhood, adolescence, and pregnancy.
According to the Dietary Guidelines for Americans 2015–2020Trusted Source, a healthful eating pattern includes a variety of foods containing it. Both animal and plant foods can be excellent sources of it.
The guidelines classify the following foods as protein foods:
- lean meats and poultry
- legumes, which include beans and peas
- soy products
Dairy products, such as milk, cheese, and yogurt, also contain protein. Whole grains and vegetables contain some of it, but generally less than other sources.
Animal products tend to contain higher amounts of protein than plant foods, so people following a vegetarian diet or a vegan diet may need to plan their meals to ensure they meet their protein needs.
The FDA advise that people can tell if a food product is high or low in protein by checking the label.
Foods that provide 5% or less of a person’s daily value (DV) are considered low.
Foods with 20% DV or more are considered high .
A person does not need to consume foods containing all the essential amino acids at each meal because their body can use amino acids from recent meals to form complete proteins. Eating a variety of protein foods throughout the day is the best way for a person to meet their daily protein needs.
Read about some healthful high foods here.
The FDA recommend that adults consume 50 grams (g) of it in a day, as part of a 2,000-calorie diet. A person’s daily value may be higher or lower depending on their calorie intake.
The Dietary Guidelines for Americans 2015–2020 Trusted Source provide the following recommended daily amounts (RDA) for protein by sex and age group:
Many factors can affect how much of it a person needs, including their activity level, weight, height, and whether they are pregnant.
Other variables include the proportion of amino acids available in specific foods that contains it and the digestibility of individual amino acids.
The USDA provide a calculator to help people work out how much protein and other nutrients they need.
Protein and calories
Is a source of calories. Generally, protein and carbohydrates contain 4 calories per gram. Fats contain 9 calories per gram.
The Dietary Guidelines for Americans Trusted Source recommend that between 10–35% of an adult’s daily calories should come from it. For children, it is 10–30%.
Most people in the U.S. meet their daily protein needs. On average Trusted Source, men get 16.3% of their calories from it, and women 15.8%.
Some diets recommend eating more in order to lose weight.
Aa 2015 reviewTrusted Source suggests that following a particular type of high-protein diet may encourage weight loss, but researchers need to do further studies to establish how to implement such a diet effectively.
When increasing protein intake, it is important to make sure that the diet still contains adequate amounts of fiber, such as fruit, vegetables, and whole grains.
Replacing processed foods and sources of unhealthful fats or sugar in the diet with protein can promote a balanced diet.
Before making significant changes to their diet, it is a good idea for a person to talk to their doctor about the best strategies and tips.
Protein deficiency due to a low intake of it in the diet is unusual in the U.S.
However, a lack of it in other countries is a serious concern, especially in children. Protein deficiency can lead to malnutrition, such as kwashiorkor and marasmus, which can be life threatening.
It is deficiency can arise if a person has a health condition, including:
- an eating disorder, such as anorexia nervosa
- certain genetic conditions
- advanced stages of cancer
- difficulty absorbing nutrients due to a health issue such as irritable bowel syndrome (IBS) or gastric bypass surgery Trusted Source
Very low intake can lead to:
- weak muscle tone
- edema or swelling due to fluid retention
- thin, brittle hair
- skin lesions
- in adults, a loss of muscle mass
- in children, growth deficits
- hormone imbalances
Protein shakes and powders contain high amounts of protein. Powders may contain 10–30 g of protein per scoop. They may also contain added sugars, flavorings, vitamins, and minerals.
In shakes or powders can come from:
- plants, such as peas or soybeans
- milk, such as casein or whey protein
Building and repairing muscle requires protein. Many athletes and bodybuilders use protein products to boost muscle growth.
A wide range of protein supplements is currently available, many claiming to encourage weight loss and increase muscle mass and strength.
A 2018 review reported that taking protein supplements significantly improved muscle size and strength in healthy adults who do resistance exercise, such as weight lifting.
However, shakes and powders count as dietary supplements, and so they are not regulated by the Food and Drug Administration (FDA). This means people cannot guarantee that the products contain what the manufacturer claims they do.
Some supplements may also contain banned or unhealthy substances, such as heavy metals or pesticides.
Many products are high in added sugar and calories, which can lead to spikes in blood sugar and weight gain, so it is important to check the labels.
Most people, including athletes, can get enough protein from a balanced diet without supplements. Getting too much it consistently can cause serious health problems.
Some people may benefit from using powder to address health concerns, including those with:
- a reduced appetite, which may result from older age or cancer treatment
- a wound that is not healing well, as protein can help the body repair and replace cells
- a medical condition, such as a serious burn, that requires additional calories and protein
For most people, a varied and healthful diet will provide enough of it. For the best health benefits, people can get their needs of it from a variety of sources. These include fish, meat, soy, beans, tofu, nuts, and seeds.
Here are some suggestions for adding more of it to diet:
- Replace regular snacks with high protein snacks, such as nuts, roasted chickpeas, and peanut butter.
- Add beans and peas to soups, side dishes, or salads. These also make great main dishes.
- Include one high food with each meal.
- Replace a source of carbohydrate with a source of it, such as swapping out a piece of toast for an egg in the morning.
- Before adding protein bars to the diet, check the labels, as they can be high in sugar.
To limit fat intake while increasing intake, choose lean meat, poultry, and dairy products, or trim the fat before eating. Try using cooking methods that do not add extra fat, such as grilling.
Avoid processed meats and other processed foods, as these can have negative health effects. Choose nutrient-rich foods instead of processed foods when possible.
Is an important part of every diet. The FDA recommend that adults consume 50 grams (g) of protein per day as part of a 2,000-calorie diet, though a person’s specific needs depend on their age, sex, activity levels, and other factors.
Most people in the U.S. meet their daily needs. If a person wants to increase their protein intake, they can do so by including healthful, high protein foods with each meal.