Finally: you have access to a list of protein sources that are sorted by the rate at which they are absorbed.
Before we start: What does absorption mean and why does it matter?
Although this might seem obvious to most, I thought that it might be a good idea to include in case there are a few readers who did not know why absorption rates are so important. The absorption rate is the rate at which the protein that you digest enters into your bloodstream and is available for the body to use for protein synthesis. Protein synthesis is the process where your body takes the protein that is available to it and turns those protein building blocks into protein. Different forms of protein take different amounts of time before they are ready to be used to form new muscle. Knowing which protein sources work faster or slower will help a lot in determining which protein to use and when. For example, using a fast protein will be best for a meal before a workout; because faster protein absorption means that your body has the broken down protein resources it needs to start repairing and growing muscle. If you are using a slower protein in this case, your body will still be digesting and breaking down this protein so it will not be ready to be used when you need it. Also, faster proteins are needed as a post workout straight after your workout. This is because the 'anabolic window' only lasts for about 90 minutes, according to most. This anabolic window term refers to the fact that a large part of your muscle growth (as a result of exercise stimulus) depends on the nutrition that you have straight after (up to 90 minutes) after your workout. The sooner after your workout that you get the precious resources that your body needs to build muscle, the more it will be able to do so. This might sound like a small difference in the grand scheme of things, but if you get a small advantage because of this every day; it will build up over time to make a very big difference. Because you want your body to have broken down protein readily available for your muscles to rebuild as soon as possible at certain times (like before or after a workout), absorption rate makes a big difference. Slower absorption rates can provide advantages as well. For example, you would want to have slower absorbing protein sources before you go to bed. That way, your body has a ready-to-use protein for a longer period of time during your sleep cycle. Imagine if the protein you take before bed is all used up before it's time and your body is left empty for the rest of your sleep. That is a lot time that you spend in a state of missing building blocks to do so. If you can have protein available in your system for a longer period of time, your body will have the access it needs to usable protein for longer so that it can spend more time building muscle. There are other reasons why absorption rates matter, like when you are using a protein supplement as a meal replacement. When you want to lose fat and feel fuller for longer, you would use a slower absorbing protein so that your body takes longer to use up the food it has before feeling hungry again. Conversely, people that need to eat more regularly but struggle with appetite will use protein that is quicker absorbing; so that it is all used up and they are ready to digest more food sooner.
Protein Supplements by Absorption Rate
Protein peptides are made specifically for this purpose. Peptides are proteins that are scientifically broken down into smaller pieces so that it is easier for the body to digest and use. This reduces the time between digestion and usage. Peptides are commonly sold to endurance athletes more than bodybuilders. The reason for this is mainly because of price. Because of the extra (and costly) processing needed to make peptides, they aren't very financially viable for bodybuilders that require protein on a larger scale. Alternatively, peptides work well for runners and other aerobic athletes because only small quantities are needed. These athletes use peptides during races when the body is breaking down from stress. Because peptides are so easily absorbed, their bodies are able to recover and rebuild DURING the race or event. Additionally, runners only need smaller quantities of these when they are using them because they're goal is to reduce muscle breakdown during a race, instead of building or increasing muscle mass.
Whey protein is the most popular protein supplement by far. Reasons for this include its fast absorption rate and relatively cheap price. Whey protein is derived from dairy (milk). Did you know that there are three common forms of whey? These three forms are whey concentrate, whey isolate and whey hydrolysate. Whey concentrate is the most natural form of whey, and is the primary form of whey once it is derived from milk. Whey isolate is whey concentrate that is further processed to increase the protein percentage. Whey hydrolysate is whey isolate which is processed once again in order to break it down further for faster absorption. These are listed below, also according to absorption. ALL of these three forms are translated into usable protein faster than the other protein supplements that follow.
Hydro whey (why hydrolysate) is the fastest absorbing protein form of the three. It is also the most processed and therefore the most expensive of the three. Not many supplement brands sell whey hydrolysate on its own because of the higher price that comes with the extra processing. Hydrolysate can often be found mixed with the other two forms of whey protein in most post-workout drinks.
Whey isolate is the second fastest absorbing whey protein. It is a processed from of whey concentrate which is made and sold because of its higher protein purity. When whey concentrate is further processed to increase the protein percentage, it becomes whey isolate. Pure whey isolate protein forms can be found on their own more easily than whey hydrolysate because it is often used as an extreme cutting meal replacement. This is because the carbohydrate content of whey isolate is extremely low (almost non-existent) and it is almost totally made up of pure protein.
Whey concentrate is the most natural form of whey protein, made directly as a result of concentrating the protein content of milk. It is therefore the cheapest of the three (since it takes the least processing to produce), but is also the slowest absorbing whey. Because of its price, whey concentrate is often the biggest component of whey protein blends.
Milk isolates are a combination of all the protein components that can be isolated from milk. While whey is the fastest absorbing and casein is the slowest (both come from diary sources), milk isolate has attributes of both of these. Part of milk isolate protein will be absorbed quite quickly while other parts of the isolate will take longer to absorb. This makes milk isolate a good source of protein for people who want fast AND slow absorbing protein from a single protein source (as you could always mix one source with another to have a combination of absorption attributes).
Soy protein is a protein supplement that is isolated from a plant source. Because it comes from a plant, it is a lot cheaper to make and therefore often serves as a 'filler' protein that supplement companies use to increase the protein content of their products without spending too much money. Soy is a good source of protein on its own and makes for a good meal replacement, but cannot beat the quickness of whey and the steadiness of casein.
Egg protein is obviously protein that comes from egg (mostly made from egg whites). This is also a good source of protein, but neither digests at the fastest nor slowest rate. Like soy, this makes egg protein a good meal replacement because it is biologically ready for the body to use at a quick rate, but doesn't run out too quickly.
Out of all these, casein is the slowest digesting protein source. One of the reasons for this is because it forms a kind of gel-like substance in your gut. This makes it harder for the digestive system to digest and will stay in your system for longer. Casein is often sold on its own for people to take before bed, as a feel-fuller-for-longer option and as a component in meal replacements to even out the rate of absorption. Casein therefore has its own advantages, but it NOT recommended as a post-workout supplement.
Did this help you with the information you wanted? Let me know in the comments below. STAY STRONG!