How much protein do we need?

Protein is one of the three most important macronutrients (proteins, carbohydrates and fats), and we need relatively large amounts of protein for our bodies to function properly.

However, opinions differ on exactly how much protein we need each day.

That’s what this article is about – how much protein we need and how our health, age, gender and lifestyle affect the amount we need.

What are proteins, and why are they important?

Protein is the basis of all living cells – our bodies (at a healthy weight) are made up of about 62% water, 16% protein, 16% fat, 6% minerals, less than 1% carbohydrates and a very small amount of vitamins and other elements.

Protein is not only necessary for the growth and repair of the body’s tissues (organs, muscles, bones, skin, hair…) but also provides us with energy, forms blood, enzymes…

There are at least 10,000 different proteins in our bodies that make us up and keep us as we are.

What are proteins made of?

Proteins are made up of more than twenty basic building blocks called amino acids.

The order and arrangement of amino acids give each protein a unique structure and function. The number of amino acids in different proteins can vary widely – from about 20 amino acids to several thousand amino acids, for example:

• Insulin is made up of only 51 amino acids.

But.

• Titin (also known as connexin), which is found in muscle fibres, consists of more than 38,000 amino acids.

Amino acids are divided into the following categories:

• Essential amino acids – amino acids that must be taken in through food because our bodies cannot synthesise them:

1. 1. Histidine (the best sources: pork chops, beef (steak), chicken breast, tuna, tofu, beans).
   2. Isoleucine (best sources: beef (steak), chicken breast, pork chops, tuna, tofu, milk, lentils).
   3. Leucine (best sources: chicken legs, beef (steak), pork chops, tuna, tofu, beans, milk, cottage cheese).
   4. Lysine (best sources: beef (steak), chicken breast, pork chop, tuna, king crab, tofu, cottage cheese, milk, beans).
   5. Methionine (best sources: turkey, beef (steak), tuna, pork chop, tofu, milk, cottage cheese, Brazil nuts).
   6. Phenylalanine (best sources: beef (steak), chicken breast, pork chops, tofu, tuna, pinto beans, milk, pumpkin seeds).
   7. Threonine (best sources: beef (steak), chicken or turkey, pork chops, tuna, tofu, soybeans (Edamame), milk, green peas).
   8. Tryptophan (best sources: chicken or turkey, beef (steak), pork chops, tofu, fish (salmon), soya beans (Edamame), milk, pumpkin seeds, oatmeal).
   9. Valine (best sources: beef (steak), chicken breast, pork chops, tuna, tofu, low-fat yoghurt, beans, green peas in pods).

• Non-essential amino acids – amino acids that our bodies can synthesise themselves (if there are enough precursor molecules), so they do not have to be consumed in the diet:

1. 1. Alanine.
   2. Asparagine.
   3. Aspartic acid.
   4. Cysteine.
   5. Glutamic acid.
   6. Glutamine.
   7. Glycine.
   8. Proline.
   9. Serine.
   10. Tyrosine.

• Conditionally essential amino acids – amino acids which, under certain conditions (for example, illness, stress, infancy, etc.) our body may not be able to synthesize in sufficient quantity and therefore they must be additionally consumed with food, for example – arginine, cysteine, tyrosine, ornithine, proline and glycine.

Different protein sources have different amino acid compositions. We can easily get all the essential amino acids from meat and dairy products.

But.

Vegetarians and vegans may have problems getting enough essential amino acids because plant-based diets have less of them.

Essential amino acids that can be problematic to obtain from vegetarian and vegan diets are:

• Good plant sources of lysine are tofu, legumes (beans, lentils, chickpeas), quinoa, tempeh and seitan.
• Methionine. Foods rich in methionine include tofu, seeds (especially quinoa and chia seeds), nuts, wholemeal products and legumes.
• Tryptophan. Good sources of tryptophan are tofu, pumpkin seeds, sesame seeds and chia seeds.

How much protein do we need?

You know, there is no exact answer to this question.

The amount of protein we need depends on our gender, lifestyle, level of physical activity, age…

The minimum amount of protein for adults is 0.8 grams of dietary protein per kilogram of body weight. However, this is the minimum amount our body needs to avoid health problems, not the amount of protein we should eat daily.

As I said, the amount of protein required depends on many factors.

Here are the protein intake guidelines for the different groups (minimum amounts):

• Children:
  • Infants (0-12 months). Breast milk or an artificial breast milk substitute usually provides sufficient amounts of protein.
  • Children (1-3 years) – 1,2 g per kg body weight.
  • Children (4-13 years) – 0,95 g per kg body weight.
• Adolescents (14-18 years) – 0.85 to 1.2 g per kg body weight (depending on growth, development and activity level).
• Adults – 0,8 g per kg body weight.
• Older adults – 1 to 1.3 g per kg body weight.
• Athletes:
  • Endurance training – 1.2 to 1.4 g per kg body weight.
  • Strength training – 1.2 to 2.0 g per kg body weight.
  • HIIT training – 1.2 to 1.7 g per kg body weight.
• Pregnant women – 1.1 g per kg body weight. Read more about nutrition during pregnancy HERE.
• Breastfeeding women – 1.3 g per kg body weight.

Remember that these recommendations are general guidelines defining the minimum amount of protein vital for the body.

Individual protein needs may vary. For athletes in particular, they can vary greatly (depending on the type, intensity and duration of training).

Pregnant and breastfeeding women need more protein to support the growth of the foetus and the infant.

For personalised recommendations based on your health condition and lifestyle, consult your doctor, dietitian or nutritionist.

I would say 10% to 35% of your daily calorie intake should come from protein. In other words, if you need, for example, 2000 calories per day, then 200 to 700 calories should be taken as protein.

Does protein have any negative health effects?

Some studies suggest a possible link between high-protein diets and kidney problems.

However.

There is no evidence showing a direct causal link between high protein intake and kidney problems.

But.

Some studies show that high-protein diets can exacerbate pre-existing chronic kidney disease. Therefore, people with pre-existing kidney disease should consult their doctor before drastically changing the amount of protein in their diet.

In general, there is no evidence that high-protein diets have a negative effect on kidney function in healthy people, but there are studies showing the health benefits of high-protein diets, for example – on bone health.

What does “gram of protein” mean?

Misunderstandings about this are pretty frequent.

In nutritional science, a “gram of protein” means how many grams of protein a particular food contains, not how many grams the protein-containing food weighs.

For example, a portion of beef weighing 226 g contains only ~61 g of protein, but a large egg weighing 46 g contains only ~6 g of protein.

How much protein can our bodies absorb?

There is some debate about how much protein our body can absorb.

For example, muscle protein synthesis in adults is thought to be maximised by the intake of ~20 to 25 g of high-quality protein, and anything above this amount is used for energy or excreted from the body.

However, this only applies to the intake of fast digestible proteins, e.g. in the form of protein drinks.

But.

Many protein sources (e.g. beef) are digested much more slowly, especially when taken with other foods. Consequently, protein absorption is slower and amino acid utilisation is better.

The truth is that we can absorb almost all the protein we eat.

But.

The amount of amino acids we can use for muscle growth, aka muscle protein synthesis, is limited.

Studies have shown that to increase muscle protein synthesis (promote muscle growth), we have, among other proteins, to take in around 2 to 3 grams of leucine per meal.

This means that the composition of our meal is as important as the total amount of protein it contains.

In other words, unless we have health problems, our bodies can absorb almost all the protein we eat. However, for muscle building, the body can only use about 30-40 grams of protein at a time, and to promote muscle growth, the meal should also contain at least 3 grams of leucine.

Key takeaways

Protein intake is vital for virtually all our body’s processes, including tissue synthesis and repair, enzyme and hormone production, immune function, maintaining and improving bone health…

Enough protein also helps to control weight (promotes satiety), making it an integral part of a balanced diet.

However.

There is no universal answer to the question – How much protein should we eat in one meal or during one day?

A good target for most people would be eating around 30 grams of protein per meal.

And.

It matters not only how much protein we eat in a day but also – what protein we eat.

See the best sources of protein HERE.

See the best protein sources for those who don’t eat meat HERE.

Start your day with a protein-rich breakfast, eat a balanced diet and – stay healthy!