It is important to consume adequate protein for health and normal bodily function. The recommended dietary allowance (RDA) of protein varies depending on factors, such as age, sex, and overall health.

Protein is a macronutrient and the main component of many different body parts. As such, it is important to consume a suitable amount to support health. However, consuming too much or too little protein can lead to health issues. Therefore, it is advisable for protein to account for roughly 10–35% of an adult’s daily calories.

This article explores what protein is, why it is important to consume the right amount, how to calculate someone’s protein needs, where to get protein from, and the risks of consuming too much or too little.

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Protein is the main component of a person’s muscles, skin, bones, organs, hormones, enzymes, and many other body parts. It makes up a significant amount of the body.

Protein is a nutrient that the body needs to create and repair cells. Protein is made up of building blocks called amino acids, some of which the body can synthesize.

There are 9 amino acids, however, that the body cannot synthesize. They need to be consumed through a person’s diet.

Protein is important because if a person has too much or too little they risk developing health conditions.

Without protein, the body may not be able to heal properly or otherwise function normally. This includes the growth and repair of cells and the production of hormones, red blood cells, and enzymes.

A person’s protein requirement will vary depending on a number of factors. For this reason, ensuring that people consume enough protein for their individual situation is very important.

The Recommended Dietary Allowance (RDA) of protein varies depending on a number of factors, including a person’s:

  • age
  • sex
  • activity levels
  • overall health
  • muscle mass
  • whether they are pregnant or breastfeeding

The general RDA for an average adult is 0.8g of protein per kg of body mass per day. However, this is a minimum level.

The Dietary Guidelines for Americans recommend that adults should get 10–35% of their daily calories from protein.

The chart below shows the recommended minimum amount of protein people should consume, based on the average sedentary lifestyle, meaning a person doing little or no exercise.

Age and sexTotal RDA in grams (g) per day
Babies and children
0 – 6 months9.1
6 – 12 months11.0
1 – 3 years13.0
4 – 8 years19.0
9 – 13 years34.0
14 – 18 years52.0
19 – 70 years and older56.0
9 – 13 years34.0
14 – 70 years and older46.0
Pregnant or lactating people
Any age71.0

Experts recommend that a person undertaking any level of activity eat substantially more than 0.8g per kg of body weight.


Infants and children require more protein proportional to their body weight than fully grown adults, as they use the protein as they grow.

Pregnant or lactating people

As shown in the chart above, the recommended protein amount that pregnant or lactating people should consume is much higher than that of non-pregnant or lactating people.


Another group that requires more protein than the average person is athletes.

Athletes can eat up to 3.5g of protein per kg of body weight daily, according to one 2016 research paper.

The same study recommends that the ideal amount of protein per kg of body weight is:

  • 1g for people with minimal activity
  • 1.3g for people completing moderate levels of exercise
  • 1.6g for people carrying out intense exercise

Increasing muscle mass

Someone trying to increase their overall muscle mass, such as when strength training, should aim to eat proportionally more protein than, for example, someone training for muscular endurance.

A person over the age of 50 who is beginning to lose muscle mass (a process known as sarcopenia), may want to consume more than the lowest recommended amount of protein to build or rebuild their muscle mass.

Recovering from injury

People who are recovering from an injury may need to consume more protein than normal to help their body heal.

People can include protein in their diet by eating both animal and plant-based sources of protein.


  • lean meats such as beef, lamb, pork
  • poultry such as chicken, turkey, duck
  • fish and seafood, such as shrimp, lobster, oysters
  • dairy products including milk, yogurt, cheese
  • eggs


People should consume some protein in every meal, as the body cannot store excess protein, so eating smaller amounts often is key.

Examples of one serving of protein include:

  • 2 large eggs
  • 2 slices of cheddar or other hard cheese
  • 1 cup of cooked beans
  • 1 cup of milk
  • 1 small can of fish
  • 2.25 oz of cooked lean meat
  • under 3 oz of lean poultry
  • 1 oz of nut butter

If a person consumes too little protein, they are at risk of developing a number of conditions. These conditions may include the following:

Muscle mass issues

If a person does not consume enough protein, they may find themselves losing muscle mass, because the muscles are mostly made up of protein.

When the body is not receiving enough protein from a person’s diet, it may tap into the reserves of protein stored in the muscle to help with more important bodily functions.

Increased appetite

When a person does not consume enough protein their appetite may increase. The body does this instinctively as a way to encourage a person to eat more protein.

Some people report feeling more hungry for savory foods rather than just in general.

Weight increase

Due to the increased appetite experienced as a result of insufficient protein in the diet, a person may find themselves reaching for ‘easy’ unhealthy foods over lean proteins. This may cause them to notice that their weight is increasing.


As well as the above issues, in some more rare instances, protein deficiency can also cause:

  • problems with the skin, hair and nails
  • fatty liver
  • stunted growth in children
  • edema (swelling)

On the other hand, if a person consumes too much protein, they may develop conditions such as:

Bone loss

Too much protein may lead to a loss of calcium from the body. This can increase a person’s risk of osteoporosis, or bone weakness.

Weight increase

Researchers have found a link between too much protein and an increase in weight, even from an early age.

One study of lactating women and their newborns suggesting that high protein in the early ages may contribute toward obesity in later life.


Too much protein consumed on a long-term basis also has been linked to:

Adequate protein consumption is crucial to sustain normal bodily function, but too much or too little protein may cause health issues.

It is important that a person eat the right amount of protein based on their needs.

People should speak to a healthcare provider, dietitian, or nutritionist before drastically changing their diet in any way.