More than ever, people like trainers, workout enthusiasts and dieters drink protein shakes as part of their daily routine. I look into what is the purpose of drinking these shakes? Do they really work? And what are the various differences between them all?

Why Protein?
Three-quarters of the solid material in the human body is composed of protein. The body uses protein to produce all its muscles and other tissues, including organ tissue, and to generate enzymes, hormones, immune system components, nucleic acids and cellular messengers.


Without enough protein the body can face the following challenges:

it can’t combine the structures necessary to compose its every organ, tissue and cell
it can’t manufacture the biochemical components required for cardiovascular function and muscle contraction
it can’t heal or grow as fast or as well, creating the greater potential for overworking the muscles and increasing risk of injury
Solid food sources of protein include eggs, dairy, meat and beans. So they offer an alternative – or better put, a supplement – to these sources.

What Are Protein Shakes?

They are drinks composed of protein in a powdered form mixed with water, milk or juice and possibly blended with other fruits, vegetables, dairy products or supplements. For the purposes of this examination, we’ll be looking at the powdered protein that forms the base of these drinks, independent of whatever other ingredients one may include in their shake.

The protein in these powders can come from several sources, most commonly whey, casein, soy and egg.

How Do Protein Shakes Work (And Do They Work)
To answer the second question first – yes, they do work, that is – as long as they are used properly.

Many people drink shakes for energy before a workout, but that is not their primary purpose. They are primarily to help the body build muscle and restore itself after exertion. For energy prior to or following exertion, carbohydrates and water are far better. It’s the carbohydrates that provide the energy boost many people associate with drinking them. There is a time when it is appropriate – and even helpful – to consume them before a certain kind of workout, but we’ll get to that in a few moments.

The science of bodybuilding is simple. Every time the muscles contract when exercising them through lifting weights or other forms of resistance training, tiny tears form in the muscle fibers called “micro-tears“. It is the job of protein to heal these micro-tears by rebuilding the muscle fiber between and connecting them.

But why a protein shake? Why not solid protein?

Protein Shakes vs. Solid Protein
In powdered form the protein is more readily available to the body – or “bioavailable” – than in solid form, meaning it’s easier to digest and absorb. Whereas the body can take 90 minutes or longer to digest solid protein and start putting it to work healing and growing tissue and cells, it only takes about 30 minutes to do it with the protein in liquid form.

Why is it so important the protein be digested and absorbed quicker? The body begins the healing and cellular regrowth process immediately upon “injury”. From this time, there is a 1-2 hour window during which the bulk of the muscle repair and rebuilding process occurs. After this window, the benefits provided by any boost added to aid this process diminish in value, and the more of the protein and other ingredients that go to waste.

Benefits of Protein Shakes
To summarize, they offer several benefits, foremost among them:

muscle repair / preventing muscle breakdown
lean muscle mass growth
strength building
increased endurance
improved immune system function
more bioavailability of protein than from solid food
larger protein quantity per volume than solid food
Furthermore, these shakes can help people prevent the reverse of these benefits from occurring – muscle damage and breakdown, weakness, tiredness, excessive appetite – caused by not having enough protein in their system following a resistance training workout.

Lastly, their convenient. It’s far easier to carry a satchel around with you than a slab of meat. And if you’re short on time, drinking down a protein shake is a lot quicker and easier than eating a meal on the go.

Types of Protein Shakes
Each of the following protein sources contains a different combination of essential and non-essential amino acids, and since different proteins in the body are formed from different amino acid chains, this means that each protein source is better for producing different types of protein in the body.


Whey is a complete protein derived from milk that possesses all the essential amino acids as well as the highest branched-chain amino acid content that can be found in nature. It boasts the quickest rate of digestion and absorption of any other protein source, producing peak levels of amino acids in the bloodstream, important because amino acid levels in the blood regulate the synthesis of muscle protein.


Casein is the main protein in milk, comprising 80% of milk’s protein content, whey comprising the other 20%. Also containing a thorough supply of amino acids, casein is a slower protein to process and synthesize, which means that it’s not as good for instant muscle repair but is excellent for long-term protection against muscle breakdown. For this reason, if they combine whey and casein will give you the best of both worlds.


One of the primary reasons people use soy protein in their shakes is if they have an allergy or sensitivity to whey or casein. Another is if they’re vegan or simply prefer a non-animal protein source. Derived from soybeans, soy protein has many of the essential and non-essential amino acids, but not all of them.

So it would be technically inaccurate to call soy protein a “complete protein”. In general, soy protein is not as quickly or easily digested and absorbed as whey or casein, lending to some people considering it an inferior protein source.

There is widespread debate, as well, about whether or not soy protein contributes to increased estrogen levels or estrogen-like effects in the body, which are counterproductive to the testosterone the body needs for strength training.


Egg protein is one of the most expensive forms of protein and therefore not as frequently seen as a prime component of protein shakes. As it comes from the egg whites it doesn’t contain any of the fat or cholesterol associated with eggs. It also lacks any carbohydrates.

Egg protein is an extremely bioavailable form of protein that for most people is easy, if not the fastest, to digest. It has an amino acid profile that’s even more complete than whey, however not as proportionately high.

Of the protein sources mentioned, egg albumen makes one of the best sources for those using protein shakes as a meal replacement.

Other Ingredients In Protein Shake Powders

Leaving out what other ingredients one might toss into their personal protein shake, like a banana or yogurt, or whether they use milk, juice or water as the liquid, powders themselves contain certain other ingredients as well.

First and foremost, most contain some amount and variety of amino acids, as they are the building blocks of protein. Of all the amino acids, among the most revered for post workout purposes are the following:

creatine – provides a bevy of benefits, not least of which is massive increase in muscle size and strength
glutamine – at the same time the body’s most abundant and most rapidly depleted amino acid, beneficial not just for building muscle but also for boosting the immune system,
branch chain amino acids (BCAAs) – namely leucine, ioleucine and valine, which support muscular growth and improve endurance
Protein shakes also frequently contain a carbohydrate source to replenish glycogen, the fuel the body utilizes during a workout. As mentioned earlier, the carbohydrates are usually responsible for the immediate energy lift theyare reputed to provide. Most contain approximately 5 grams of carbohydrates and about 20-25 grams of protein per scoop.

Protein shakes typically contain added vitamins and minerals for supplemental nourishment as well. Some even contain blue-green algae or other “superfoods” for that same purpose. Many also contain acidophilus and other bacteria beneficial for digesting all the ingredients in the shake.

How to Choose the Best Protein Shakes

The most popular measurement of a protein’s “quality” is its Biological Value (BV) or how much nitrogen 100 grams of the particular protein – in an adult’s diet – can replace. The theory is that the higher the BV, the greater the protein at facilitating growth.

The higher the protein’s BV, many believe, the better it is digested and utilized, and therefore, the more protein the body retains, meaning the more lean muscle mass it gains. It should be noted, however, that this has not been proven, and some scientists dispute the notion.

Never the less, as one point of evaluation, here are some helpful BV comparisons. Whey has the highest BV produced in nature, at about 104, which helps explain why it is so commonly used. Compare that against the foods with the next highest BVs in line.
Beyond BV, another key factor influencing which protein source is best is the individual’s workout goals. A faster acting protein like whey, for example, is better for someone trying lose weight while they build lean muscle, whereas a slower-acting protein like casein is a better weight gainer for someone trying to bulk up and build sheer muscle mass.

For those who insist on replacing meals, casein provides a more sustained source of protein nourishment for the long term, though egg albumen provides the most.

Lastly in choosing a type of protein shake, remember that some people may have a sensitivity to certain protein sources. People who have a dairy sensitivity, for example, shouldn’t use whey or casein protein. Others people, however, find soy protein difficult to digest.

Determining which protein sources are more amenable to your digestion is a matter of knowing your body or, for lack of that, a bit of trial and error.

How Much Protein To Take?

The general rule for building muscle is to take in at least 1 gram of protein per day per pound of body weight. Any quantity greater than that only helps speed up the process of healing and regrowth.

Is There Such A Thing As Too Much Protein

The debate about whether or not a person can consume too much protein still rages on. A common sense approach might be to suggest that moderation in everything is generally a good rule to go by and that anything more could be too much. Others protest that you can never get too much of a good thing. Who’s right?

Well whoever is right, one thing both parties may be able to agree on is that a risk people take with eating too much protein at once is difficulty digesting it all. If this seems to be the case for you, typically evident by symptoms such as gas pains, cramps and sluggishness, then you have two choices: consume less protein or add more calcium and magnesium.

This is because excessive protein in the body can deplete supplies of calcium and magnesium, which are utilized in protein synthesis.

Beyond calcium and magnesium depletion, the other problem with excessive protein consumption is that unused protein is eliminated from our body through our bowel movements.

More unused protein means more waste. It takes energy for the body to process waste, and the energy your body would be using to process an overabundance of protein is energy the body could be using instead for some other purpose, such as burning calories, for example.

The other obvious drawback of consuming more protein than your body needs is cost. Taking in too much protein, especially if you’re providing that excess in the form of protein shakes, which can be expensive, can also be a waste of money.

When to Use Protein Shakes?

After Strength Training

If consuming them as part of a strength-training workout regimen, then for maximum benefit you should drink the shake immediately after the workout. As mentioned earlier, the first 1-2 hours after weightlifting or other resistance training workout is the most critical time period for muscle repair. Whey protein, for its fast-acting bioavailability, is an ideal source for a post-workout beverage.

Before Cardio

As alluded to earlier, there is a situation in which drinking one before a workout could be useful, and that is before a cardiovascular workout.

While it’s the carbohydrates in the mixture that provide that feeling of an instant energy boost, regardless of when you drink the shake, by drinking it before aerobic exercise you protect the lean muscle mass from being burned to provide the rest of the energy needed for the workout.

Consumption may not provide much energy for a cardio workout beyond its carbohydrate content, but it will make sure that the energy produced in the body during that workout is from fat and not muscle.

A combination of fast-acting whey protein and slow-acting whey protein is probably the best bet for a pre-cardio workout.

Before Bed

Protein shakes are also invaluable right before bed. During our sleep, the body slowly depletes its available protein supply.

Supplementing this with a quickly and easily available form of protein that doesn’t require the sleeping body work too hard to digest it can be a great help in the body’s natural process of rebuilding and restoring itself while you sleep.

Immediately noticeable results of this could be greater feelings of vigor and strength when you wake up the next morning that are more sustained as you proceed with your day.

Casein and egg protein, because of their slow-acting properties, are ideal choices for a pre-bedtime protein shake.

More info from wikipedia.

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