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How much protein do you need to gain muscle?

Man eating protein with caption how much protein do you need to gain muscle

As a scrawny and self-conscious teenager, I thought it was important to get hench. As a vain and only-slightly-more-secure adult, I’m still trying, sort of.

Whenever I’ve read up on how to do this, it seems clear that getting protein is important to building muscle. But how much, of what type, and when? That bit’s more confusing. So I looked into a load of evidence, and here’s what I found.

What’s the potential upside?

Apart from trying to show off, what’s the point in building muscle? Here are some of the claimed benefits – note that some of these are the benefits of strength training, rather than getting the right amount of protein per se, but as protein will help with the object of that training i.e. building muscle, we can assume that getting the right protein will account for some of the effect.

  • Long-term health. Building muscle helps maintain your ability to perform everyday tasks as you age. Along with flexibility training, it may reduce the risk of breaking bones, of falling, and mean you’re able to continue active hobbies for longer.1 This is probably not a huge concern when you’re young, but gets more important with age. The Mayo Clinic says strength training can also help manage chronic conditions such as back pain and depression2, but I would expect most of this is from the training itself, rather than the muscle building.
  • Increased exercise motivation. The more benefits you see from exercise generally, the more likely you are to stick to it. So getting the right amount of protein might encourage you to do more exercise overall, both of the cardio and strength variety (assuming you’re trying to build muscle, rather than lose weight).
  • Positively shapes your diet? It seems reasonable that basing your diet around a positive goal such as protein consumption is a better way of keeping off unnecessary fat than focusing on the negative of reducing/restricting calories.
  • Social perception. Being in ‘better shape’ might have benefits for how others perceive you, which is good for social situations, getting jobs etc.3 Being more muscular won’t make your face prettier, but it might overall help a little.
  • Greater metabolism. You burn more calories (even at rest) if you have more muscle.4 Having a good metabolic rate will help staying in shape, particularly as you get older.
  • Self-esteem. It’s an ego boost to look more muscular, even if that probably shouldn’t be your main reason.

Comment: These benefits are uncertain, and hard to identify or measure when they do come. You probably get most of the upside by doing strength training 2-3x per week, assuming your existing diet isn’t completely lacking in protein. But particularly as your long-term health is so important, it’s still worth considering the question further.

Some rough principles

Based on the evidence I covered in this research, these are the rules of thumb I would follow:

  • You should aim for between 1.6 and 2.2 g/kg body weight of protein per day to increase muscle mass. 2g/kg is a decent rule of thumb to remember.5
  • There is evidence you can synthesise really large doses of protein in a single meal (especially if you don’t get loads of other protein in the same day), so don’t worry too much about the distribution.6 But you probably want to make sure you have enough protein and carbs around a workout to make the most of the workout. And it can be hard to get all the calories in if you spread them across fewer meals.7
  • To actually increase muscle size, you probably need to be in calorie surplus, as well as having enough protein.8
  • You need all the ‘essential’ amino acids (i.e. the ones the body doesn’t self-generate) to synthesise protein, so make sure you’re getting all of these on a regular basis.9
  • A lot of sources recommend you have whey protein (isolate) after a workout, as whey is absorbed more quickly than many proteins (10g per hour, as opposed to 3g per hour for egg). But it’s not clear that it results in overall greater synthesis.10 Absorption is just the rate it gets into the bloodstream, rather than the rate it turns into muscle. Eating a normal meal that contains a good helping of protein is probably fine (again, as long as you can manage getting this down – a protein shake is often easier and cheaper).
  • If you’re getting protein from food rather than shakes, chewing it properly might help a little with protein synthesis.11
  • There is some evidence that intermittent fasting (IF) diets are good for losing fat whilst maintaining muscle mass12, but you might find it harder to gain muscle if you’re on an IF diet. Some anabolic (growth) markers are down after you’ve been on an IF diet13, and it can be difficult to get the required calories down in a smaller window.
  • That said, you don’t need to worry you’ll lose all your muscle if you miss breakfast. Just eat that breakfast on top of whatever you would have had later.
  • How much protein you synthesise for muscle growth is also dependent on your size (the bigger you are, more protein you’ll be able to synthesise), what sort of exercise you do (big compound exercises are likely to result in greater overall protein synthesis), your age (the older you are, the less you’ll synthesise for growth)14, and almost certainly some genetic factors.
  • It’s easy to focus on ‘gains’, but you shouldn’t overlook the maintenance of muscle mass. A significant factor in whether you’re in good shape is probably avoiding big periods of atrophy, where you have low protein intake, little exercise, illness etc.15 So be consistent. And if you’re not doing weight training, at least go for a little walk before you eat, as that signals to the body that you want to use some of the incoming protein for muscle synthesis.
  • You don’t need to give up on gaining muscle when you’re older, but you probably need bigger doses of protein.16

What is the evidence, and how good is it?

There’s tonnes of research related to this topic, and it’s hard to digest (no pun intended) because it’s not all trying to answer the same question. I could only scratch the surface, but felt like the review paper I read gave a good overview. A few things to note:

  • The main contention in the literature seems to be over the claim in Areta et al (2013)17 that you can only synthesise around 25g of protein per meal. However, as Schoenfeld and Aragon (2018) point out18, that study was based on only having whey protein isolate, and only gave the subjects a total of 80g of protein. Evidence from other studies19 suggests you can synthesise more, but the evidence doesn’t seem to be overwhelming either way.
  • My prior beliefs were that you need to eat a lot of protein to put on muscle – body builders do, it fits with my understanding of how muscle growth works, and it gives me an excuse for never having got bigger than I am.
  • There are big incentives in nutrition science to sell you stuff you probably don’t need. And it seems to get a lot of attention in the media, so there are probably bad incentives there. So I’d generally be quite skeptical of the science generally.
  • I maybe put too much weight on the review paper because it’s well-written and narrative i.e. I could understand it better than some of the individual studies.
  • A decent amount of the good information is probably held by professional sports people, and not available to the public.
  • There aren’t loads of large-scale RCTs, longitudinal studies, studies across populations etc.
  • I’m not aware of studies (or even anecdotes) which show the opposite effect i.e. lower protein causing increased muscle growth, or even of a much lower amount being sufficient for muscle growth in people doing a lot of weight training. But I think I had previously swallowed the idea in Areta (2013) that any protein you consume over-and-above 25g is essentially wasted.

What’s the potential downside?

  • Cost. Protein-rich meals tend to be more expensive, particularly if you don’t eat meat. That can be mitigated if you get cheap, protein-rich meal replacements, but you could still eat cheaper.
  • Potential for overthinking. The link between protein consumption and muscle building has the potential to be a mind virus, of the sort described in this podcast. In other words, once you think you should be getting enough protein, you overthink it, and get unhappy when you don’t consume enough. That said, if you’ve read this far, you’re probably already infected 😅.
  • Possible health costs. I didn’t see anything suggesting negative effects of too much protein – it seems like you’d have to eat a lot for that to happen. But if you get too much from a single bad source, like eating a tonne of burgers every day, that probably isn’t good for you. A dodgy protein shake seems the most likely way this would happen for me. It’s also important not to forget other important things – vitamins and minerals – in the quest for more protein.

Comment: These seem small to me. And the most important concern – negative health consequences – is very low risk.

Is it worth it? My thoughts

Trying to maximise muscle gain following the principles above probably isn’t going to make a huge difference to your life. But the costs are sufficiently small and risks sufficiently low for this to be worth doing for me.20

How the calculation shakes out for you depends on how much you value the costs and benefits, and how you view the various risks. If you think I’ve overlooked something significant in this calculation, please leave a comment!

How to do it?

It’s pretty hard to get 2g per kilogram of bodyweight into your system every day without a) paying a lot of money b) eating meat or c) spending a silly amount of time preparing and eating food. I mainly do it through meal replacement shakes, namely Huel and Benu.21 Nuts are another cheap and protein-rich food, but you don’t want to overdo it on just nuts, especially the salty version I like.

What to do next? When to review?

If you’re uncertain about a course of action, it’s good to consider what would make you change your view, and how you could go about gathering that information. Here are some ideas:

  • Measure the size of your muscles on a regular basis / take ‘before and after’ pictures
    • I’ve tried a bit of this, and it’s sufficiently annoying to have already stopped. Without proper equipment, it’s very hard to measure your muscles in the same way each time. And there’s too much else changing in my exercise and diet at the moment for this to be reliable.
  • Have another review of the available evidence after a certain amount of time
    • I plan to do this in ~5 years. It seems like there’s potential for there to be a lot of new evidence in this time, but it’s not worth me doing sooner because the expected benefits aren’t huge.

Sources

Footnotes

  1. According to the NHS website, accessed 11 July 2022.
  2. See this page, accessed 11 July 2022. It also mentions research showing strength training and aerobic exercise may help improve thinking and learning skills for older adults, but (annoyingly) doesn’t link to the research.
  3. See, for example, this 2016 study of 100 university students, where perceived attractiveness was shown to correlate with perceived academic performance. There’s even some suggestion that your physical appearance shapes your character – see, for instance, this BBC article from 2019. That could be a good or bad thing.
  4. According to the Mayo Clinic accessed 11 July 2022
  5. According to this 2018 literature review (PDF version). To quote: “to maximize anabolism one should consume protein at a target intake of 0.4 g/kg/meal across a minimum of four meals in order to reach a minimum of 1.6 g/kg/day. Using the upper daily intake of 2.2 g/kg/day reported in the literature spread out over the same four meals would necessitate a maximum of 0.55 g/kg/meal.”
  6. See this paper and discussion in the section ‘Higher acute ‘anabolic ceiling’ than previously thought?’ of this paper
  7. This is especially true of protein, which makes you feel more full (mentioned in this podcast).
  8. This seems pretty uncontroversial, but also listen to S3 E19: The Science of Nutrition in Sport with Prof. Graeme Close
  9. “the amino acids derived from protein actually play a dual role in muscle growth: In addition to being a source of raw materials, protein acts as a signaling molecule, triggering the growth of new muscle. One amino acid in particular, leucine, seems to be the most potent anabolic signaler, but you need all the amino acids together to effectively build muscle.” – according to this profile of Luc van Loon, Professor of Physiology of Exercise and Nutrition at Maastricht University
  10. According to Bilsborough S, Mann N. ‘A review of issues of dietary protein intake in humans’. Int J Sport Nutr Exerc Metab. 2006;16(2):129–52., so might get a greater spike from the whey, but more overall from the egg, because it ‘may attenuate oxidation’.
  11. I got this from this profile of Luc van Loon, Professor of Physiology of Exercise and Nutrition at Maastricht University, which refers to this study showing ground beef is digested quicker than steak. There were only 10 people in the study though, so I wouldn’t put much weight on it.
  12. See, for example, this randomised controlled trial of 34 men: fat mass was reduced by 16.4% in the intermittent fasting group, versus 2.8% in the normal diet group, whilst fat free mass was maintained in both (but note that the normal diet group consumed around 200 calories more per day)
  13. According to the same study
  14. See this nice video from Jeff Nippard, which covers a lot of the literature.
  15. See this study, and discussion in the profile of Van Loon
  16. See this randomised controlled trial of 62 elderly subjects where the protein-supplemented group were able to put on (modest amount of) muscle.
  17. Areta et al (2013), Timing and distribution of protein ingestion during prolonged recovery from resistance exercise alters myofibrillar protein synthesis’, Journal of Physiology, 591(Pt 9):2319–31.
  18. Schoenfeld and Aragon (2018), How much protein can the body use in a single meal for muscle-building? Implications for daily protein distribution, Journal of the International Society of Sports Nutrition (2018) 15:10
  19. Such as Mcnaughton et al (2016), The response of muscle protein synthesis following whole-body resistance exercise is greater following 40 g than 20 g of ingested whey protein, Physiological Reports, 4:15.
  20. I appreciate this is a privileged position to be in, and not everyone will be able to do this sort of deliberate change to their diet.
  21. You can get the latter for about £2.65 per 100g of protein if you’re lucky.