Whey Protein: The Definitive Guide to the Protein Powder

Protein powders, protein shakes and protein bars – protein has got very popular.

For many people, these products are just the latest fad, but for others, getting enough protein in the diet is a critical part of their health and their lifestyle.

Of all the options out there, the best hands down is whey protein, and no, it isn’t just for bodybuilders.

But, what is whey protein good for?

Well, whey protein is a high quality, quickly absorbed form of protein that can contribute to weight loss, muscle gain, improved cardiovascular health and much more.

Why Whey Protein?

Whey protein has become a pretty big deal in recent years, particularly for bodybuilders and people trying to improve their health. But, it isn’t even obvious what exactly the protein actually is.

As the name suggests, whey protein is a mixture of proteins that have been isolated from whey. Whey is found in the watery fraction of milk. In the production of cheese, the fatty parts are used to form the cheese while the watery component is discarded.

This is then used to produce the whey powder that is becoming increasingly popular (1).

In fact, you may have seen whey itself before, without realizing it.

When you open yogurt, there is often a layer of liquid that floats on top. This layer is the whey. While the whey used to be discarded in cheese making, the demand for whey protein has made it a lucrative product (2).

The two main reasons for this are the nutritional properties of whey protein along with the functional properties that it offers food. From the nutritional perspective, whey contains important minerals as well as lactose and proteins.

Functionally, whey protein works well with food and liquids because of its solubility (3).

One of the biggest aspects of taking whey protein is the protein side of things. This isn’t the only answer to 'what is whey protein good for' but it is a pretty major one.

Because of this, protein is a topic that we are going to come back to a few times over the course of this article.

Not only is protein important, but it is also highly controversial. There are a lot of different viewpoints out there about how much protein you should be having.

I will address these controversies later on in the article and provide evidence. For the moment though, take my word that protein is a very important part of the diet – and many people aren’t getting enough.

Whey protein is particularly important as a source of protein because the protein is absorbed quickly into the body, more so than most other sources of protein (4).

Indeed, whey protein is considered as fast protein, which means that it is absorbed quickly in the body. This may make it particularly relevant for slowing the processes of protein loss that typically occur during aging (5).

Whey protein also has a higher protein quality rating than most other proteins (6). This makes it a fantastic choice as a way to include protein in the diet.

Nutritional Components

Whey protein contains a mixture of different proteins.

The image below shows how the proportions of these proteins, although the proportions may not remain the same in the final protein powder that is sold.

The most prevalent of these is β-lactoglobulin (beta-lactoglobulin) and the second most common protein is α-lactalbumin (alpha-lactalbumin). Other important proteins include serum albumin and immunoglobins (7).

These proteins have a range of different potential impacts on health. For example, α-lactalbumin can change the ratio of amino acids, promote increased serotonin activity and improve mood (8).

Many of these proteins are branched-chain amino acids (BCAAs). This type of amino acid plays a role in increasing muscle synthesis and potentially energy as well (9,10). Research has even indicated that BCAAs may play a role in increasing lifespan overall (11).

Other components of whey are also important. One example of this is lactoferrin, which is an important part of the human immune system (12).

A pilot study also indicated that lactoferrin could inhibit the progression of the hepatitis C virus in the body (13).

Indeed, whey protein itself has been proposed as a viable treatment for patients with chronic hepatitis B, although the study did not find significant changes in patients with chronic hepatitis C (14,15).

Likewise, L-glutamine is another compound that offers significant health benefits.

In particular, L-glutamine can help to improve the gut. This includes helping the intestines in repairing and rebuilding (16), as well as helping to heal ulcers (17). One research study on patients with HIV found that L-glutamine can also help to reduce the severity of diarrhea (18).

Indeed, L-glutamine is so significant for health that some people choose to take it as a supplement. Whey contains a significant amount of essential amino acids and these may be critically important for increasing the benefits associated with physical activity (19).

This outcome isn’t just beneficial for body builders, but for anyone who is trying to lose weight or get healthier in general.

For example, whey protein is high in cysteine, an amino acid. Cysteine is significant, because it has the ability to increase the production of glutathione. Research has illustrated that supplementation with whey protein can indeed increase plasma levels of glutathione (20,21).

Glutathione has many key functions. In particular, it is a powerful antioxidant (22,23), helps to regulate the nitric oxide cycle (24) and plays an important role in iron metabolism (25).

By its nature, whey is a complicated product and we do not fully understand the biological function and potential benefits of all components of the proteins that make up whey. This means that whey may offer many as-yet undiscovered benefits to health.

Health Benefits of Protein

Protein, Muscles and Body Composition

Within the body, muscle is constantly being built up and broken down. Protein plays a key role in this process and getting enough protein in the diet is needed to build muscles (26).

When people try to lose weight, a common approach is to decrease the amount of calories that they take in. This pattern often means that people cut out many good sources of protein. If you don’t consume enough protein, then the process of weight loss will cause you to lose both weight and muscle (27,28).

The pattern is a frustrating one, and far from ideal. Realistically, you want to be losing fat while increasing your muscle mass.

One reason for this is appearance. Some people lose weight to improve their health, but for most of us, the desire to look good is a major factor in the decision.

When you lose weight and muscle, you end up in a situation known as skinny fat. People who are skinny fat might be small and have a good overall weight, but they have a body fat percentage of 30% or above.

A second thing to consider is health. There are a lot of health risks associated with being overweight, including metabolic syndrome, increased risk of diabetes and increased risk of heart disease. Your percentage of fat plays a role in the health issues associated with obesity.

This means that if you just drop your weight without paying attention to your body composition, you may still be at risk. In fact, many people who look visibly healthy and thin are actually very unhealthy, and may not even be aware of it (29).

After all, we live in a society that is obsessed with the idea of being thin.

With all that pressure, it is easy to put too much emphasis on weight and not enough on health.

Researchers are beginning to strongly emphasize the idea of skinny fat (which they call normal weight obesity).

People with normal weight obesity are those who have a normal BMI, but their body fat percentage is high (30).

One study looked at data from 6,171 participants on a range of factors, including BMI, body fat and cardiovascular risk factors. The authors then divided the subjects into groups and compared outcomes for the group with the higher level of normal weight obesity versus the lowest level.

They found that the group with high levels of normal weight obesity were more likely to have cardiovascular disease (in the females) and hypertension (in the males). Likewise, this group had an increased risk of death from cardiovascular disease (31).

As I mentioned above, protein can play a significant role in helping people to gain muscle (32). This is one of the reasons why bodybuilders frequently supplement with whey protein, as do many people casually looking to gain a bit of muscle.

Increasing protein, in general, can help with this process.

Whey protein is a common choice because of its other health benefits, along with the fact that it can be easily added to healthy smoothies and consumed without hassle. This makes whey protein a much more practical solution in many cases than increasing protein intake through protein-rich meals.

Weight Loss

Protein is also highly relevant for weight loss. In general, losing weight successfully involves burning more calories than we take in.

Of course, this is much easier said than done, as anyone who has tried to lose weight through dieting will know.

Protein can help with this in two ways

First, protein can help to boost the metabolism, increasing the amount of energy that is used (33,34,35).

For example, one study examined outcomes in 10 females during either a high protein or a high carbohydrate diet.

The authors of the study found significant differences in nitrogen balance between the two groups, which indicates a difference in energy expenditure (36). Even though the study was small in scope, it offers an indication of the differences in energy expenditure, something that the other cited studies also indicate.

Much of the increase in energy used comes from an increase in gluconeogenesis (37). This process is the metabolic pathway involved in the production of glucose.

The second way is even more significant.

Eating protein can significantly decrease appetite and help people to feel full for longer. For example, research has shown that people on a high protein diet tend to feel less hungry compared to other diets.

In some cases, this can significantly affect the amount of calories that people take in, especially for people who are actively trying to lose weight (38).

For example, one study had female participants increase the proportion of protein in their diet from 15% to 30%. The authors of the study found that by doing so, the participants lost weight and ate fewer calories in a day (39).

A study in obese men showed that higher protein meals significantly decreased appetite and contributed to improved appetite control (40). These outcomes are particularly important for anyone trying to lose weight, as they mean that eating more protein can potentially make it easier to make good decisions about food.

The absolute best way to lose weight is to change your lifestyle in a long-term manner (41).

Getting more protein in your diet can be one very good way of making a positive long-term change. The fact that you feel hungry much less often makes it so much easier to stick to a dietary approach.

Myself, I have found that having a high protein diet means that I crave sweet foods much less.

First and foremost, whey protein is an effective way to get protein into the diet.

The bulk of research into the topic of whey protein and health has been strongly focused on protein itself and the role that protein can have on health.

Nevertheless, there have been some studies that have directly considered whey protein and its implications for health, muscle mass and weight loss.

Whey Protein and Weight Loss

​Any consideration of 'what is whey protein good for' really has to start with a consideration of weight loss. After all, weight loss is the reason that many people choose whey protein to begin with.

A particularly important study in this area was a meta-analysis that looked at randomized controlled trials considering the impacts of whey protein on body composition and body weight.

In total, the meta-analysis included 14 different randomized controlled trials, with a combined total of 626 participants.

The authors found that the majority of studies analyzed supported the potential of whey protein to help improve body parameters, both in terms of weight loss and muscle gain (42).

One of the key reasons that whey protein is so effective for weight loss may be because of how fast it is absorbed.

Additionally, whey protein offers an important way to get protein into the diet without a substantial addition of calories. For people trying to lose weight, this can be important – and it’s one reason that protein shakes, in general, are so popular.

Interestingly, whey protein has also been shown to have glucose-lowering properties for people with diabetes (43). However, research into that aspect of whey protein is still in its very early stages.

Cardiovascular Health

Whey protein is strongly associated with significant improvements in risk factors for cardiovascular disease.

Some research suggests that the compounds in whey protein may be the reason that increased dairy consumption is associated with significant health benefits (44).

One study considered the impacts of whey protein in a sample of 70 overweight men and women. As part of the study, the participants were broken into three groups. One group received supplementation with casein, one group acted as the control (and received a glucose supplement), while the third group supplemented with whey protein.

All groups received supplements that were visually identical and contained the same amount of energy. Both the casein and the whey supplements contained 27 g protein.

The authors found that supplementation with whey protein significantly improved vascular function and blood pressure in overweight and obese participants (45).

A similar outcome was found in a study that supplemented with fermented milk that contained whey protein (46).

Another study found that whey protein was able to reduce blood pressure and also improve measures of arterial stiffness (47).

That particular study looked at both whey protein and milk protein in general. Both had an impact on blood pressure, but the whey protein was the only one that impacted arterial stiffness. Some of the bioactive compounds of whey also contribute to improved cardiovascular health.

This occurs through decreased blood pressure and through other mechanisms

These outcomes suggest that whey protein can reduce the risk of heart disease and other health conditions by reducing risk factors.

Implications for Cancer

Whey protein has the potential to play a role in protection against cancer and in cancer treatment (48). A key reason for this is the glutathione antioxidant system, which is an important system for protecting cells (49).

For example, glutathione can help to protect against cell death from oxidants (50). Because of this, there has been a substantial amount of research into the impacts of the glutathione molecule.

Research suggests that whey protein supplementation may provide a significant anti-tumor impact for some types of cancer because of this system (51).

Including protein in the diet, such as adding in whey protein, has also been recommended as a way to contribute to a protective diet that could reduce the risk of cancer (52).

How Does Whey Protein Powder Compare?

If you go to the grocery store, you will see all types of protein powder. Whey powder is one example, but there are many others as well. This should be an indication that many people already have their own opinions about 'what is whey protein good for'.

In fact, the selection is large enough to be extremely confusing, especially to people who haven’t done much research into the different types of powder.

This is a particular issue when it comes to weight loss and people often don’t know what to choose.

To make matters worse, whey protein tends to be marketed more towards body builders, while other brands are focused on weight loss.

One critical example of this is the brand Slim Fast. This is marketed as a ‘protein shake mix’. That isn’t really the same as a protein powder, but many consumers won’t realize the difference.

The very first listed ingredient is sugar, followed by cocoa. In fact, protein itself doesn’t turn up until part way through the list. This explains why the powder tastes so good and why it mixes well with milk, but that doesn’t help with weight loss.

The ingredients list might come as a surprise, because the marketing on the front of the tin says this:

10 grams of protein per serving is relatively decent for a protein powder. There are better of course, but that doesn’t sound too bad. There’s a catch though, just look at the text under the claim.

So, the 10 g of protein includes the milk you prepare it with (assuming you even prepare it will milk). In reality, the powder itself only contains 2 g of protein per serving.

That’s a really low value.

In comparison, I want to look at one brand of whey. I’m choosing this one because it is actually what I have in the house at the moment, so I’m not saying that it’s the best in the market or anything like that.

In this case, the very first ingredient on the list is the protein (specifically, a blend of whey protein concentrate and whey protein isolate). Sugar doesn’t even make the list, and instead the brand uses stevia (a natural sweetener). Even then, the sweetener is quite a way down the list.

Protein-wise, this brand has 18 g of protein for one serving of the powder.

This makes it much more filling.

The two powders have roughly the same serving size in terms of weight and are also very similar in calories. The whey protein is 100 calories per serving, while the Slim Fast is 110. However, in terms of volume, you do get more from a serving of the whey (on the left) compared to the Slim Fast (on the right).

Despite the similarities between the brands in terms of calories, there is a major difference in where the calories come from.

So, with Slim Fast, you are getting most of your calories from sugars and a bit extra from fat. For Designer Whey, most of the calories are coming from protein, which is what you actually want.

This means that Slim Fast will do little to affect your hunger, where whey powder can actually be an effective replacement for a meal. Overall, these differences show that many protein products marketed for weight loss don’t actually do well at this task.

I know this from my own experience too. A smoothie made with Slim Fast might keep me full for an hour or two if I’m lucky while an identical smoothie made with whey instead will keep me full until it’s time for the next meal.

It’s pretty clear which of the two approaches is best for weight loss.

Now of course, there are other brands and types of protein powder out there that aren’t as bad as Slim Fast, but there are many like Slim Fast that are marketed as something that they really aren’t.

This is a concerning practice and a far too common one.

The prevalence of this practice makes it so important to learn about the protein powder that you plan to take and how it compares to other brands and types out there.

There are a huge number of options for whey out on the market now. You can find brands in the supermarket, in health food stores, and even from many MLM companies.

However, there is a lot of variation between the products.

One thing to look out for is the ingredients. A key concept of taking whey protein is the health benefits that it offers. You undermine this benefit if you aren’t careful when you choose what to buy.

In particular, a number of companies add refined sugar or other unhealthy additives into their product. This is a concerning practice, because you don’t want added sugar if you are trying to lose weight.

In many cases, sugar is actually the second ingredient on the nutritional label. That’s a lot of sugar and all it does is improve the taste of the powder (sometimes it doesn’t even do that).

There are better ways to improve the taste, without relying on sugar to do it.

Types of Whey Protein

In general, whey can be broken down into two key categories: whey concentrate and whey isolate.

Whey concentrate is the most common form of whey protein and it is also the least expensive. Because of this, many of the cheaper whey protein products will probably have whey concentrate in it.

Whey concentrate contains between 70% and 80% protein, with relatively low levels of fat and lactose. The price makes whey concentrate the most popular type of whey protein.

Additionally, it also tends to taste better.

Whey isolate, on the other hand, tends to be a more expensive form of whey protein. It is much higher in protein (upwards of 95%) and has fewer other components.

Because of this, whey isolate tends to be absorbed faster and is the best approach for getting protein into your body quickly.

In general, these differences make whey isolate more desirable.

However, whey isolate is also more purified than whey concentrate. This process means that some of the useful compounds in the protein are no longer active, such as immunoglobulins and phospholipids.

Nevertheless, the process used to create whey isolate does not change the amino acid sequence of the whey protein, so both types are effective for muscle building.

Finally, there is a third type of whey protein that is less common, known as hydrolyzed whey isolate. This is a form of whey isolate that has been broken down further.

This results in a similar pattern, where hydrolyzed whey isolate is absorbed faster than whey isolate (and whey concentrate), but contains fewer nutrients. Likewise, whey isolate is absorbed faster than whey concentrate (53).

Overall, these differences mean that there is a tradeoff between how fast the protein is absorbed and the nutrients that it contains. It is also worth noting that most of the research into whey protein has focused on the isolate rather than the concentrate form.

It is likely that the health benefits are similar across the different forms, but more research is needed to know which form is the most effective.

Some companies try to get ahead of this debate by using a combination of two (or more) forms.

For example, the brand Designer Whey uses a blend of whey protein isolate and whey protein concentrate (although they do not specify how much they use of each).

Ultimately, which form you choose is going to depend on your own needs and your budget.

If you are trying to get in as much protein as possible, or if you want to reduce calories as much as possible, whey protein isolate is a better choice.

In contrast, if you have a limited budget or want more potential health benefits, whey concentrate may be the way to go. For most people, whey protein concentrate (or a product that mixes concentrate and isolate) is probably the best option, especially because of the price and the taste differences.

However, if you have problems tolerating whey concentrate, or if you are trying to keep carbs and fat as low as possible, then whey protein isolate, or whey protein hydrolysate, offers a good alternative.

There are a lot of whey protein brands out there, and these vary considerably in terms of quality and price.

Ideally, you would want to buy the highest quality whey protein possible, with the fewest added ingredients and the highest protein content.

In practice, this is easier said than done. When it comes to buying food and health supplements, most people have to find a balance between how good the product is and how much it costs.

Whey protein is a very good example of this because even the lowest quality whey tends to be expensive, much more so than some other types of protein powder.

For example, it’s pretty common to see tubs of whey protein for upwards of $50 and even the smaller containers are often more than $20.

What you end up going with will depend on your own needs and finances.

Despite the cost though, it really is worth picking up whey protein and including it in your diet. If the price really is an issue, start off with a small container and go from there. This is a good way to figure out what particular brand and flavor works for you.