Blog Post

How to Optimise Post-Workout Nutrition

A guide to post-workout nutrition

The post-workout period is a timeframe that can be important for maximising muscle growth and recovery. It is typically less important than your overall nutrition each day, but it still plays an important role.

There are quite a few aspects to consider when it comes to post-workout nutrition. And often there are a lot of questions too. This post is designed to cover it relatively succinctly.

If you want to understand how and why all this matters, read the full post. If you simply want to know what to do, jump to the summary at the bottom.

Protein and the Anabolic Window

One of the first things I heard about when I first got interested in post-workout nutrition was the anabolic window.

At the time, I heard people talking about it as if to maximise muscle growth, you needed to get in a fast-acting protein such as whey within an hour of your workout.

Man drinking a protein shake

I then later heard people dismissing the anabolic window. These people promoted that all you needed to focus on was consuming enough total protein. This was more of an If It Fits Your Macros type of approach.

The answer is somewhere in the middle. Both total protein intake and protein timing matter. But the window is usually not as small as an hour.

Protein Prioritisation Pyramid

Currently, the consensus is that the anabolic window is a 3–5-hour window around the time of training.

Further Understanding the Anabolic Window Timing

This 3-5-hour window is quite a general range. It is worth examining it a bit deeper.

Firstly, it involves both the pre-workout and post-workout periods. You can think of this as 1.5-2.5-hours pre-workout OR post-workout.

A great example of this is research comparing pre-workout to post-workout protein supplementation leading to the same results.

The 5-hour aspect really is more relevant if you have a lot of protein a few hours pre-workout. This is because it takes time to digest and absorb. It can still be in your system post-workout.

If you train fasted, this means you have a <1.5-hour window where you want to be getting in a decent amount of protein.

This also explains why there is quite a bit of research that makes it look as though the anabolic window is only an hour or so long. A lot of research is done in a fasted state to control variables.

How Much Protein

The amount of protein to maximise muscle protein synthesis is typically around 20-40g.

It is based on size. People with more muscle mass need more than those with less.

A more accurate guide is to aim for >0.4g/kg. For somebody who is 80kg, this would be 32g.

Some people interpret the research on this topic as if it is a limit to how much protein we can digest and absorb that we should never go above.

Muscle protein synthesis in response to different amounts of protein

I have a different perspective.

We know that total protein intake matters far more than this. The current consensus is that to maximise muscle growth, we should be aiming for 1.6-2.2g/kg per day. For that same 80kg person, this is 128-176g per day.

If you limited yourself to NEVER having more than 30g of protein in a sitting, it would be difficult to achieve that total number.

As mentioned previously as well, if you have a larger amount of protein, it takes longer to digest and absorb. Although it may not raise muscle protein synthesis further in the acute timeframe, it still can play a role in muscle growth if it helps you consume enough total protein.

Type of Protein

The common logic is that whey protein is a fast-acting protein and casein protein is a slow-acting protein. Therefore, people believe that whey protein is a superior post-workout protein option.

Whey vs Casein Digestion Speed

This makes sense at a surface level but falls apart when analysed closely.

Firstly, the moment you mix whey protein with anything, the digestion rate significantly slows down. Even adding milk would slow it down to the point that it is digested roughly as quickly as casein with milk.

Secondly, this hypothesis is easy to test. Based on this logic, whey protein post-workout should lead to more muscle growth than casein post-workout.

When studied though, they both lead to the same outcomes.

whey vs casein effect on muscle growth

This is good news. It, alongside other research, means that we do not actually need to focus much on choosing fast-acting protein.

We also do not need to use supplementation either. It is a convenient option, but we can use food.

Really all we need to do is focus on getting that >0.4g/kg of protein in through either food or supplements. Almost all decent protein sources will work.

One guideline that you will want to meet is to aim for >2g of leucine.

Leucine is an amino acid that is helpful for triggering muscle protein synthesis. It is not the only thing that matters. But choosing a protein source that ticks this box will also likely work well for muscle protein synthesis.

Carbohydrates and the Anabolic Window

Carbohydrates post-workout are sometimes proposed to help with muscle growth. The mechanism this is often linked to is insulin.

The idea is that carbohydrates spike insulin. Since insulin is a storage hormone, this could help facilitate protein being stored as muscle.

This is another easy hypothesis to test. Theoretically, research should show that this leads to more muscle protein synthesis and muscle growth, if true.

That is not what the research has found though.

Insulin not further increasing muscle growth

Adding carbohydrates in addition to protein post-workout has not led to additional muscle protein synthesis. It is not detrimental, but it does not add further benefit.

Another aspect that is often overlooked is that protein can raise insulin as well. The chart below demonstrates this well.

Graph showing protein + carbs raising insulin more than carbs

Training Multiple Times in a Day

While the above section implied that carbohydrate post-workout is irrelevant, there is a big caveat to that.

If you are training again soon, it is important to get carbohydrates in as soon as possible to replenish glycogen.

Typically, this applies to people who are training multiple times per day. It could also apply to somebody who is training late in the evening, and then again in the morning.

Glucose is our body’s best fuel source for performance. Glycogen is our body’s storage form of glucose. When glycogen gets depleted, performance typically gets worse.

If you have fast-absorbing carbohydrates after your workout, you put yourself in a better position for that second training session.

To maximise replenishment, you would want to aim for 1.2-1.5g/kg of carbohydrates every hour.

Use common sense though. Prioritise sleep over this, if relevant.

If the event is >6 hours away, there is no need to continue doing this approach. And if you do not need to maximise replenishment, which most people do not, you can go considerably lower than this amount.

If you are not training again for a while, just focusing on consuming an appropriate amount of carbohydrates for the day is all that matters.

Fat and Fibre Content

Dietary Fat

Fat and fibre slow down digestion and absorption.

From the muscle protein synthesis side of things, this likely does not matter much.

For rapidly replenishing glycogen stores it could matter more. Slowing down digestion would slow down how quickly glycogen is stored.

If you are training again soon, ideally you would want your post-workout meal to be low in fat and fibre. If you are not training again soon, it does not matter much.

Who Should Care About All of This?

The people who should care about this are:

  • People trying to maximise muscle growth.
  • People trying to maximise recovery.
  • People trying to optimise performance in training sessions that are close together.

Total nutrition for each day matters a lot more than this stuff too. You do not want to consistently focus on this aspect if it undermines what you should be doing for the overall day.

Pyramid of Nutrition Priorities

If you are not actively trying to maximise any of those things, you likely should not stress about trying to optimise post-workout nutrition.

Practical Summary

Post-workout nutrition can help maximise muscle growth and recovery. If you want to implement it well, I recommend doing the following:

  1. Have 20-40g of protein within a few hours post-workout. If you have not had any protein for a few hours pre-workout, try and get this in within 1.5 hours. If you have had protein pre-workout, you have a larger window.
  2. The type of protein often does not matter much assuming your total protein intake for the day is high enough. But ideally, aim for protein sources that will contain >2g of leucine. It can be in either food or supplement form.
  3. If you are training either multiple times per day or are training again in the morning after an evening session, aim to get in >30g of easily digestible carbohydrates directly post-workout.
  4. If you need to quickly replenish glycogen stores, as in the above scenario, then you should also aim to keep the fat and fibre content of the meal/snack low.
  5. Focus on total daily intake more than the post-workout period. They both matter. But total daily intake matters more.
By Aidan Muir

Aidan is a Brisbane based dietitian who prides himself on staying up-to-date with evidence-based approaches to dietetic intervention. He has long been interested in all things nutrition, particularly the effects of different dietary approaches on body composition and sports performance. Due to this passion, he has built up an extensive knowledge base and experience in multiple areas of nutrition and is able to help clients with a variety of conditions. One of Aidan’s main strengths is his ability to adapt plans based on the client's desires. By having such a thorough understanding of optimal nutrition for different situations he is able to develop detailed meal plans and guidance for clients that can contribute to improving the clients overall quality of life and performance. He offers services both in-person and online.