What is protein and why is it important?

Protein is a very essential macro nutrient and probably the most important among carbohydrates and fats. Protein performs some of the very crucial tasks in your body like maintaining the strength of the muscles, connective tissues and bones, maintaining the proper acid base balance in the body, maintaining the proper energy supply, regulating hormones, maintaining the fluid balance, supporting immune function etc. Every single cell in your body is made up of protein therefore, it is necessary to eat sufficient amount of protein for good health.

What are amino acids and why they are important?

Every protein is made up of molecules called amino acids. Amino acids are of two types essential and non-essential. Essential amino acids are those which our body cannot make on its own and they are required to be taken on regular basis through protein rich foods, Non essential amino acids are those which our body can make on its own and are not required to be taken on regular basis. There are total of 9 essential amino acids (Tryptophan, Valine, Threonine, Isoleucine, leucine, lysine, phenylalanine, Methionine and Histidine) each one of them having their own important function. Amino acid leucine for example is very important for building muscle.

Amino acids are important because we eat protein not just for protein but to get amino acids. Each protein rich food has it’s own amino acid profile. In order to be properly utilized by the body a protein must contain all the 9 essential amino acids in appropriate quantities, if any one of the essential amino acid is present in low quantity the protein is considered insufficient to support growth and maintenance of our body. Check out the concept of limiting amino acid below to know further about this.

Limiting amino acid

In a protein rich food limiting amino acid is something that is present in low quantity relative to other essential amino acids. The lack of this amino acid limits your ability to use the protein at its full potential. As stated above all the nine essential amino acids must be present in appropriate quantities, even if a single essential amino acid is not present in right amount the whole process of using protein for various biological processes comes to a halt.

For example: Kidney beans are a great plant based protein source, They contain 24g of protein per 100g of quantity however, they are primarily deficient in amino acid methionine. So, per serving you are getting enough protein from kidney beans but because they have a limiting amino acid(methionine) you will not be able to utilize other essential amino acids present in them. This means that not all the protein from kidney beans will be absorbed. However, eating kidney beans with rice fixes this problem to a certain extent because methionine in rice makes up the missing methionine content of kidney beans.

Protein quantity versus Protein quality

When it comes to calculating our protein intake we always go for a mindset “more protein equals better results” but ignore the thing which matters the most and that is protein quality. Thinking about protein in terms of quantity is often useless because the quality of protein you eat is more important than the amount of protein you eat. Why this is so? let me explain.

Do you know that 18g of protein from one food can build more muscle than same amount of protein from another food? this is because different foods offer different quality of protein and protein quality is determined by the content of essential amino acids. Not every protein rich food offers all the essential amino acids in appropriate amounts, some foods have greater content of essential amino acids than others.

For example: Milk and eggs are considered an excellent protein sources because they contain all the essential amino acids in significant amounts to support growth and maintenance of the body. Their amino acid profile is so good that they are used as reference protein. Such kind of protein is used to assess the quality of other proteins. (Reference protein is one such protein that is highly digestible and has content of essential amino acid similar to human protein)

Low quality protein or incomplete protein on the other hand is the one that contains all the essential amino acids but not in amounts to meet the body’s requirement. Plant based proteins often fall into this category, such proteins are often deficient in one or two essential amino acids. For example kidney beans are deficient in methionine.

Well, certainly the quantity of protein you eat matters especially when you are tracking your intake for purposes such as bodybuilding but if you are eating majority or all of your protein from poor quality protein sources it does not matter even if you eat high amounts of protein you will not get the benefit of eating that much protein because not all of it will be absorbed by your body.

To illustrate further, Let’s take two people X and Y with same bodyweight, both of them are fond of health and lift weights and eat significant amounts of protein to meet their protein intake. Let’s say person X eats 100g of protein per day and person Y eats 120g of protein per day. However, person X experiences greater gain in muscle mass than person Y, why would this happen if Y is eating 20g of protein more than X? The simple answer lies in the quality of protein. Person X eats foods of higher quality protein such as meat, milk, eggs and seafood whereas Person Y eats most of his protein from poor quality protein sources like lentils, beans, nuts, peanuts etc. and little from animal sourced food (meat, milk, eggs and seafood).

Protein from animals is different than protein from plants

You may believe that it does not matter from where I get my protein, as long as I am eating enough protein through my diet I should have no problem. Right? Wrong! It certainly matters from where you get your protein. Protein from lentils, pulses, beans, nuts, peanuts, soy is not same as protein from meat, milk, eggs and seafood. nutritional fact that protein from meat, milk, eggs and seafood is far superior to protein from plant based foods. Even if you combine different plant based protein sources to complete all the amino acids you may still end up with a limiting amino acid.

Another thing is that majority of the protein in vegetables is in the form of non protein nitrogen which humans cannot utilize! So, counting protein from vegetables seems to be useless.

Let’s take a look at amino acid profiles of some protein sources.

The following data comes from https://tools.myfooddata.com/protein-calculator/ 

Lentils and rice 

1 cup of cooked lentils contain 18 grams of protein. At first this seems to be a high protein food but it can be clearly seen that they are deficient in amino acid methionine. So, even though you are getting enough protein from lentils you cannot utilize all of it.

You can combine them with another cup of rice to make up the methionine content. The protein content of this meal goes up to 21g but still you are not getting enough methionine.

Let’s say you add 100g of tofu to this meal since, its made with soy and it is one of the best plant based sources of methionine. You end up with 29g of protein but methionine is still very deficient in this meal.

Soy and soy products which are a very popular protein foods among vegetarians and vegans do not offer as much methionine.

29g protein and 496 calories from the above meal but not a very great balance of amino acids.

Compare this to amino acid content of some common animal proteins.

Eggs and Milk

Let’s say you eat a meal consisting 3 whole eggs and a cup of whole milk, this is what you get.

See this? This meal provides you almost same amount of protein(27g) as the meal of lentils, rice and tofu(29g) but the amino acids are much more balanced and in greater quantities. Also to note that with the above plant based meal you have to eat 133 more calories to get same amount of protein but LESS essential amino acid in comparison to eggs and milk. Remember? the greater and more balanced amino acids a protein has the better it gets absorbed and utilized by the body.

 Steak

This is what you get in a a 75 gram serving of beef steak. 21 grams of protein, 200 calories and a great balance of amino acids.

These are just some examples to show you that animal based protein is far superior in terms of quality than plant based proteins. Other common plant based protein sources such as peanuts, oats, chickpeas, nuts are almost always deficient in one or two amino acid and do not qualify as good quality protein. You can still meet your protein requirement by eating different plant based protein sources throughout the day but it takes a lot of effort to do this. This can be done with much less effort by eating animal based protein. Because even when it comes to quantity animal foods are more protein dense than plant based proteins. They provide more protein in less calories. You can very efficiently meet your protein requirement by eating meat, milk, eggs and that too is high quality protein whereas it takes a lot of effort to do the same with plant based protein sources.

How to get more protein in your diet?

1.Eat the right protein

Plant proteins are inferior to animal protein nutritionally. Animal foods are not only great source of quality protein but they also offer many other vital nutrients at the same time such as zinc, B12, iron, vitamin A, D, E, K and many other minerals which are not found in plant based proteins. Whatever animal based protein is available to you and affordable to you enjoy that as part of your meals. Include whole milk, cheese, yogurt, whole eggs, beef, lamb etc. If you are a vegetarian at least drink a lot of milk and eat 4-6 eggs a day. Animal protein is essential because it all comes down to amino acids you are getting not just amount of protein. you are eating.

2.Focus more on quality rather than quantity 

When tracking your protein intake don’t just count your protein from every single food assuming that I am meeting my protein requirements rather make sure that majority of the protein comes from animal sourced foods. The importance of essential amino acids cannot be stressed enough. You need to get enough of them because if you eat adequate amounts of protein does not mean all of it will be absorbed.