Fast & Slow Proteins - Choosing wisely for maximum results

Reflex Nutrition - Jan.15.15

Fast, slow and medium proteins are becoming increasingly popular descriptions for protein powders. During 2015 they are going to be the big talking point because more and more research talks about the digestion rate of proteins and either the positive impact on protein synthesis (muscle building) or ability to prevent catabolism (muscle breakdown). If you want to use protein powders to their maximum effect you really need to understand what all of this means to you, so let's start with a simple explanation of each of the 3 types:

Fast Digesting Protein

A fast digesting protein is a protein that is typically digested within 1-2 hours and includes the two big hitters, whey protein and hydrolysed whey protein. Standard whey protein will typically be digested within 2 to 2 ½ hours, whilst hydrolysed whey protein (whey that has been pre-digested) will be digested within 1 to 1 ½ hours.

Medium Digesting Protein

A medium digesting protein is a protein that is typically digested within 3 to 3 ½ hours and includes a number of proteins such as whole egg protein, egg white protein, pea protein and rice/soy protein.

Slow Digesting Protein

A slow digesting protein is a protein that is typically digested and utilised over a period of more than 4 hours and typically the one protein that is used in this case is casein in its various forms. So a typical weight lifter or body-builder wanting to pack on muscle will be able to take advantage of these different digestion rates throughout the day to maximise their potential recovery and growth of muscle tissue. It’s a case of interpreting the latest scientific research to ensure you are taking the correct protein at the correct time of day, it is important to realise though that it will be virtually impossible to follow the research from studies to the letter because the studies will often dictate that the athletes within the studies not eat before the study or stick to a certain diet. In the real world this never happens and I’m therefore going to do my best to translate these findings for everyone so that the findings can be used in the real world to great effect. So let’s break this down into three times of the day which I see as relevant to nearly all athletes, it's something simple and easy to understand. These three are going to be Post Workout, Between Meals and Bedtime.

Post Workout

If you are aiming to build muscle as fast as possible then your training will need to be intense and effective, I’m not going to talk about training here but your aim is to trigger growth or protein synthesis. We want the same from a protein powder post workout and it stands to reason that you want to choose the protein that delivers the biggest impact on protein synthesis and it is factually the best time to take a protein shake. The most recent scientific studies show that between 20 and 40 grams of whey protein or a protein blend will work nicely. Interestingly a high quality protein blend (like Reflex 3D Protein whey/casein/egg etc), according to more recent scientific studies, seems to have an edge over whey protein. I’m keen to see what 2015 brings in terms of new research to further confirm this, it seems very likely that high quality blends will be proven to be superior to whey alone.

Between Meals

If you are serious about building muscle you already probably know that eating 5 or 6 meals/portions of protein per day is the best way to achieve your goals and I’m using the general rule of thumb of 2 grams of protein per kg of bodyweight as an example. So for me being around 85kg that’s an easy 28-30 grams of protein per meal/shake. The average time period for me between meals is around 3 hours and sometimes more, so a medium digesting protein should fit the bill perfectly. Scientific studies show that to keep protein synthesis sustained for more than 2 hours a protein blend is superior to whey. Now a whey protein shake will do the job but not as well as a protein blend. The message on this one is quite straight forward, use a protein blend for best results and the next best thing will be whey. One trick you can employ if you don’t have a high quality protein blend is to simply add milk to your whey protein shake to make it a protein blend – its easy and cheap and means you can get away with buying your favourite whey protein.


This is very straightforward and there is really only one protein source you should consider and that is casein or Micellar Casein. A very well respected scientific study showed that Micellar Casein increased leucine levels in blood (arguably the athletes most important amino acid) for a period of 7 hours whereas whey only lasted 3 hours after which blood levels of leucine quickly dropped.


This is by no means the perfect answer but its going to be a massive help to people who think that just taking whey all day is the answer. The other really important thing to realise is the quality of the proteins you are taking whether they are whey protein or a protein blend. Protein blends especially need very careful attention. You need to know the ratios of protein and the types. For example Reflex 3D Protein uses a blend comprised of 45% Native Whey Protein, 45% Micellar Casein and 10% Egg White Protein. A proprietary blend that many other supplement companies use will not tell you the ratios and that doesn’t help you if you are looking for a quality blend with significant portions of fast, medium and slow digesting proteins. Finally, as mentioned, we’re going to be seeing more and more protein blends coming to the market during 2015 so don’t forget to choose wisely![ux_latest_products title="Purchase these products!" products="3" columns="3" cat="protein-shakes" orderby="sales" type="normal"]