No one nutrient gets greater focus in the sports and performance world than protein – and for good reason. Protein builds and powers our muscles and with that comes strength and performance gains – something just about every athlete wants to have more of. Understanding how dietary protein improves muscle mass, strength and performance is crucial. Two topics that are hotly debated are the role of protein type and timing around a resistance training program. And they’re the topics I’m going to tackle in today’s podcast.
Protein. It’s the star of the sports nutrition world and absolutely essential for building and maintaining muscle mass and strength and through that, improve performance. There is probably not a single case in sport where more muscle wouldn’t be a bad thing to have. But delving into the world of protein can be a minefield as once you get past estimates of protein requirements for different athlete groups, you soon run into the two big questions: what form of protein is best and when is the best time to have it? The questions though are more about what is optimal as athletes can thrive and excel on a whole range of different diets. So the questions are better framed on if there is a clear benefit to one form of protein over another and if there are better times to focus on having protein meals or supplements around strength-based exercise designed to increase muscle mass.
But keep this point in mind as I cover this topic today that no-one eats just one form of protein and we eat food and protein throughout the day. This podcast is more about whether if greater focus could be put on one form of protein over another and if there are times during the day and around training when it is more important to hit protein goals. And more about just what those protein goal recommendations could be later in the episode.
With that being said, let’s dive in.
There has been a lot of research looking at protein and its effect on muscle mass, muscle strength and physical performance. So while individual studies are always interesting to look at, sometimes it is worth pausing and seeing what message the bulk of the research has to say when you look at it together.
And that was the topic of a recent network meta-analysis. A network meta-analysis is a statistical technique that compares multiple treatments or interventions simultaneously. By combining information from different sources, it allows the comparison of interventions that have not been directly compared head-to-head in a study.
What it means is that you can look at the effects of a range of different protein sources and timings and how they translate into improved muscle mass, muscle strength and sports performance. For the analysis I’m covering today, it included 116 randomised controlled trials involving over 4,700 healthy adults with about two-thirds men and one-third women. Trials ran from a short 4 weeks right up to almost a year and a half. Muscle mass, muscle strength and physical performance were the key areas of interest. All outcomes were compared to a placebo control or another timing or type of protein supplementation.
When people consumed protein varied and included before exercise, after exercise, during the day and before bed. As for the sources of the protein, they included plant proteins such as soy and rice, animal proteins from meat, fish and chicken foods and also cow’s milk either as whole milk or yoghurt or the ever-popular supplements of whey and casein. Although a few studies did look at things like collagen, insect protein and bovine colostrum. And I’ll link to the review in the show notes. https://pubmed.ncbi.nlm.nih.gov/38039960
So what did the study find?
Taking on protein of any type after exercise could increase fat-free mass by 0.5 kilograms and muscle mass by about 0.3 kilograms. This was in stark contrast to taking on protein before and after exercise which could increase fat-free mass by almost 2 kilograms. Protein supplementation before sleep was most effective for improving handgrip strength which is a functional measure of muscle protein as well as improving leg press strength.
So far, pretty clear and unsurprising that protein helps with muscle mass and strength, though it would appear that there is a case to be getting additional protein pre- and post-exercise and that having some before bed could have benefits too.
Okay, so how did the different sources of protein compare? They all were effective though the review found evidence that animal sources may have a small edge. It was whole dairy milk, whey protein, casein protein, and yoghurt as well as red meat and mixed protein sources that were effective for gains in both muscle mass and strength.
Showing the danger of over-analysing study results though, you can get yourself well into the weeds when you read that the review found that mixed protein sources were most effective for improving fat-free mass and handgrip strength while cow’s milk and red meat improved lean mass in the arms and legs. It’s not really suggesting that you need to eat different foods for different results, only that when you slice and dice the study results enough you will find some apparent differences that may not be that important.
Translating this all into where the rubber hits the road regarding physical performance on a range of speed and agility tests, neither the type of protein nor when it was taken had any clear effects as far as showing a difference one way or another between protein form or timing.
So there is a lot going on here, but what does it all mean? The research review does lean towards prioritising animal protein if a person chooses to eat animal foods in their diet while eating or supplementing different forms of protein before or after exercise and before sleep appears optimal.
But hold things there for one minute, because when you look at previous research reviews around the topics of protein form and timing that used different ways to assess the literature you do get slightly different answers. In research that I’ve covered in previous podcasts around protein, earlier meta-analyses and narrative reviews found that protein timing around exercise is less important – so long as you were hitting your total protein goals for the day. And in research that will make my vegetarian listeners happy, there is also research to show that plant protein is just as effective as animal protein for muscle synthesis – again, so long as you can meet your total protein goals.
So which research finding should you believe? Well, there is a case for animal-based protein as many studies, as too the findings of this latest review, appear to give it an edge for muscle protein synthesis. This is because of the amino acid profile of animal protein, especially its content of essential amino acids like leucine which are important for stimulating muscle protein synthesis. Protein and of course dietary choices though are also informed by personal preferences and even ethical considerations so it may be the case of optimising as much as possible within your own personal situation. If you have no problem with dairy foods, then whey and casein protein are worth giving a spotlight to.
What about timing though of when you should give greater focus to a protein meal or supplement if muscle gains are your focus? Again, the most recent review says it is important while past reviews say that it isn’t that important. The different conclusions could come down to the way the research has been analysed as they each used different statistical methods to analyse the data. One way allows you to compare similar types of studies – an apples-with-apples approach. While the other way, which was the method of the network meta-analysis used in this latest review, used an apples-with-oranges approach as it allows for the comparison of multiple interventions, even if they have not been directly compared in a head-to-head study. This is useful when you have so many different variables of protein type and timing. Anyway, I won’t put you to sleep with a deep dive into statistics today. I’ll just say that different conclusions can be valid – it all depends on the data and the quality of it you are analysing.
I can reliably say though without any doubt that protein is important. Getting enough of it is even more important. And whether it be from an animal or plant should be more about personal preference. And considering that athletes do have higher protein needs than the general population, then it may just be more convenient to have it throughout the day to meet those needs so before and after exercise and before sleep seems like a great way to do this while potentially optimising your gains too.
One final caveat before you run off and start hacking your diet, protein and timing to the nth degree for optimisation. The majority of the studies included in the review that looked at protein timing didn’t do a great job in ensuring similar levels of protein intake between the control and intervention groups which means there is a good chance of bias in the results favouring those with higher protein consumption. So those who were changing their protein timing likely had the edge in that their overall daily protein intake was greater than the control group. And remember what I said earlier in the podcast that my overall take on the research is that meeting overall protein requirements is the most important – the type and timing may just be icing on the cake.
So that leads me to the final topic of today then: just what sort of protein goals should an active person be aiming for? To answer this question, let’s first explore how much protein sportspeople need. Consensus position statements such as those produced by the American College of Sports Medicine give the range of 1.2 grams to 1.7 grams of protein per kilogram of body weight. The Australian Institute of Sport also gives a similar range of 1.2 to 1.6 grams of protein per kilogram of body weight.
Higher recommendation ranges can sometimes be seen of 1.6 to 2.4 grams per kilogram of body weight, but this is for athletes who are on weight loss programs and are trying to add or maintain muscle bulk while losing weight at the same time.
The top end range of 1.7 grams per kilogram of body weight though is for elite endurance athletes, athletes in strength and power sports and those in the early stages of a strength training phase as they ramp up their gym training. The ‘recreational athlete’, which describes the vast majority of active sportspeople, only needs to aim for the bottom end of the range which is around 1.2 grams per kilogram. Which as a fun fact, is the average amount of protein a typical Australian adult eats each day just from their regular diet – no protein supplements required.
Sportspeople are more focused on protein in their diet than the average person. So just how much protein do you think they would get from their normal diet on average? Dietary surveys show the normal diet of strength-based athletes provides around two grams of protein per kilogram of body weight per day. And that’s before using any protein powders.
But is there much benefit to eating protein above the upper limit range? If there is, it is hard to see a difference in clinical trials. A 2017 systematic review of 49 studies looking at protein supplementation in resistance exercise training, which I’ll link to in the show notes, found that as protein intake goes up, so too does muscle strength and size. But this maxed out at 1.6 grams per kilogram of body weight. https://bjsm.bmj.com/content/52/6/376.long
So, let’s wrap all this up. For sports people and those wanting to boost their muscle gains in the gym, it is the total amount of protein you eat over the day that is likely the most important factor in improving muscle mass and strength. Animal protein sources may have a small edge, but that doesn’t mean vegetarians will be left much behind and unless you’ve drunk the carnivore diet Kool aid, plant protein is a feature of just about everyone’s diet to an extent.
As for protein timing, this is more controversial if timing matters a lot. Especially if you consider recent research that turned the idea on its head that we are limited to how much protein we can utilise at one time and gave evidence that even amounts up to 100 grams could be used and promote protein synthesis over a 12-hour period. But even the authors of this research were quick to say that their research would unlikely change protein timing recommendations as really, who would want to be eating most of their protein needs for the day in a single meal? I’ll link to a great sports nutrition blog post on this research study in the show notes. https://www.mysportscience.com/post/rethinking-protein-intake-needs
Naturally spreading meals and protein from different sources over the day is something that comes naturally to many sports people though from the research, I wouldn’t be discounting at this stage the potential benefits of a protein nightcap.
So that’s it for today’s show. You can find the show notes either in the app you’re listening to this podcast on, or else head over to my webpage www.thinkingnutrition.com.au and click on the podcast section to find this episode to read the show notes.
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I’m Tim Crowe and you’ve been listening to Thinking Nutrition.
