Do you REALLY need protein after a workout?

Image result for drinking protein shake
Do you REALLY need protein after a workout?
What the science says and what you SHOULD do 

You've heard it before - consume protein after your workout to maximize your gains! Unfortunately, you've been misled, and let me explain why...

Nutrient timing consists of taking certain macronutrients at an optimal time to maximize recovery and performance. The most common example of nutrient timing is the belief that protein needs to be ingested immediately after a workout to maximize protein synthesis and muscular "gains". Some researchers have proposed the idea of an "anabolic window" - a limited period of time following an exercise session when training-related adaptations are most likely to occur. Specifically, the idea is that by consuming protein immediately after a workout (often in the form of a protein shake), you can maximize the rebuilding of muscle tissue that was damaged during your training session. However, recent evidence has challenged this notion, and there now appears to be no large benefit to protein timing during the anabolic window. 

Much of the research on nutrient timing has looked at how having enough protein in a day can help aid muscle tissue damage, and muscle growth. Protein DOES help you do this, undoubtedly. One of the primary roles of protein metabolism is to repair and maintain tissue, including your muscles. So it makes sense that adequate protein is vital to getting those muscular adaptations from training in the gym. The one thing we know for sure about protein, is that

You need to consume enough protein in your day, 
but the timing is not so important 

The most important thing when it comes to protein is that YOU HAVE ENOUGH of it to help repair and grow new tissue (see below for HOW much you need). There is even recent work to show that MORE might be better, and supplementing with protein can definitely maximize muscular adaptations. However, there is a lack of evidence to show that taking protein immediately following a workout is optimal. In fact, there are studies to show that the benefits of supplementing with protein are just as beneficial up to 5 hours post-training, because the muscle rebuild process starts 1-3 hours after the conclusion of the workout (Study Link). 

So while the timing of protein ingested doesn't appear to significantly affect muscle growth, there are still ways to maximize your gains through a post-workout shake. Despite the common belief that protein ingestion is absolutely required , there is instead a growing belief that; 

The timing of CARBOHYDRATES are more important 
following a workout, and not protein

Carbohydrates come in the form of glucose (in the bloodstream), or glycogen (stored in the liver and in the muscle), and they are what primarily fuels us during our workouts. Because they are a "fast" fuel source (i.e. anaerobic metabolism), our body prefers to use them when performing resistance or high intensity interval training. Therefore, it makes sense that after an intense training session, we REPLENISH our glycogen stores, in order to optimally perform in our next workouts. In order to bring glucose in to the cell, and store it as glycogen, our body relies on a process called facilitated diffusion through a transporter called the GLUT4 transporter (don't get too hung up on the details). These GLUT4 transporters are required (along with insulin) to maximize glycogen recovery. We know that following exercise and muscular contractions, the GLUT4 transporters are translocated closer to the cell membrane, making it easier to bring glucose into the cell and replenish our glycogen stores (STUDY LINKWhat this means is that

following your workout, your cells are more RECEPTIVE to helping you recover your carbohydrate (energy!) stores

Image result for glut4 glucose uptake
Figure 1. Glucose uptake using the GLUT4 transporter

Practical Suggestion:
After your workout, focus on replenishing your glycogen stores with carbohydrates from a high glycemic index, and if you're worried about your overall daily protein intake, then a scoop of whey protein may be beneficial. 

How much protein you DO need
The recommended daily allowance (RDA) of protein is 0.8g/kg body weight. However, this is for the general population, and if you are taking part in a resistance training program, you should consume at least 1.0-2.0g/kg body weight of protein, depending on training intensity. In some cases (training 4+ times per week), consuming upwards of 2.0-3.0g/kg body weight of protein has been shown to be beneficial to muscle synthesis. In fact, recent research has shown that the previously held belief that too much protein can be harmful to your kidneys may not be true, and that there may be no negative effects to large amounts of protein intake when combined with resistance training (LINK HERE). 

When Protein SHOULD be taken after a workout
Protein ingestion following a workout has shown little to no greater benefit when total daily protein intake is accounted for. However, this applies to individuals who follow a generic eating schedule (3-4 meals a day). Recently, the use of fasted cardio has been promoted as a way to shed those excess fat stores. By performing aerobic steady-state exercise first thing upon waking, and before eating, the notion is that you "kick-start" your metabolism and fat loss can be accelerated. I'm not going to get  into details on that topic (keep your eye out on another article for that), but it IS true. When fasted, your body relies on the breakdown of triglycerides (fats) and preserves its glycogen (carb) stores. Therefore, in some cases, fasted cardio can be a means of decreasing body fat. However, its very important; 

if you ARE performing fasted cardio, 
then you SHOULD be taking protein after your workout. 

Because in a fasted state, your amino acid (protein) pool is deficient, your body is more receptive to muscle synthesis, and thus it would make sense to provide immediate protein (and carbohydrate) ingestion (as described in THIS study).

Thanks for reading,

Kalan is a Human Performance Expert & Ph.D. Candidate who aims to optimize YOUR performance in both sport and every day life. He is recognized as a Certified Strength & Conditioning Specialist (CSCS) with the National Strength & Conditioning Association (NSCA), and has obtained his Master of Science in Kinesiology degree at the University of Victoria. Through his masters thesis research, Kalan has established and implemented the KFit Test Battery for Combat Sport Athletes which is used by Karate BC, Boxing BC & Karate Canada as their standard fitness test for athletes across the country. Additionally, Kalan is an exercise prescription & physiology lab instructor at the University of Victoria, and trains individuals every day to help meet their fitness needs and goals. He has many years of experience both as an elite athlete and high performance coach and is knowledgeable in the many fields surrounding human performance.