March 6, 2024

Nutritional Biochemistry

Optimizing protein quantity, distribution, and quality

Maximizing muscle protein synthesis is more than a matter of daily protein intake. How we distribute protein throughout the day matters, as does protein quality.

Peter Attia

Read Time 8 minutes

Whether you are the type who eats to live or lives to eat, protein intake is a foundational part of nutritional planning to increase or maintain lean mass as you age. Dietary protein provides amino acids, which are essential for building new tissue, repairing old tissue, and conducting basic cellular functions throughout the body. In the human body, protein is formed from 20 different amino acids. Of these 20, nine are deemed “essential” because our bodies cannot synthesize them and must instead obtain them through our diet. 

Unfortunately, the recommended dietary allowance (RDA) of 0.8 g protein per kg body weight per day is only the minimum amount of protein needed to maintain nitrogen balance and is far too low for goals of increasing lean mass and minimizing the risk of sarcopenia, especially as we age and become anabolically resistant. How much protein each individual requires is more complicated and depends on sex, body weight, lean body mass, and activity level, but essentially, if you under-consume protein, your body will use its own lean mass as a source of amino acids, leading to loss of muscle mass. The Acceptable Macronutrient Distribution Range (AMDR) is 10-35% of caloric intake as protein, which is 1.0-3.7 g/kg/d for the average 57-kg woman or 70-kg man. For those who are minimally active, the lower end of this range is probably sufficient to maintain lean mass. However, those who want to increase their lean mass or who partake in moderate or intense physical activity should try to consume higher levels of protein to promote strength and skeletal muscle growth, up to around 1.2-2.2 g protein/kg body weight/day.

In our practice, we aim for the upper half of this range, or about 1 g per pound of body weight (2.2 g/kg body weight/day), but optimizing your increase in lean mass through muscle protein synthesis (MPS) via protein intake is more than a matter of how much protein to eat – it also depends on how that protein is distributed over the course of a day, as well as on protein quality.

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  1. Hope you will cover the most recent protein study from Trommelen et al. suggesting no upper limit to protein ingestion, it has blown the roof off the common narrative of having to space out protein intake throughout the day. Previous research used whey protein, this study used milk protein thus containing more of the slow digesting casein fraction. One would assume that mixed meals would have the same effect. We still don’t know whether the net anabolic effect of e.g. 4 x 50g or 5 x 40g would equal 2 x 100g (OMAD studies seem to indicate that 1x200g would not be a good idea)…

  2. What are your thoughts on supplementing with essential amino acids (EAA) for the fasted morning workouts or supplementing EAA’s in general?

  3. Peter,

    Would you please post some recommended protein supplements? I am currently using the Kos protein powder which is plant based. This article encourages me to rethink that choice in favor of non plant based protein supplements….suggestions?


  4. Peter,
    If I workout with weights twice a week, for example, do I need these levels of protein every day ? I’m assuming that MPS has a specific duration after each muscle is stressed in a single workout. What is that duration and is it correlated to the muscle soreness post workout ?

  5. Is there a good resource for learning more about protein digestibility and digestion rate? For example, most of us have heard that whey is fast and casein slow to digest, but what about egg white, chicken breast? Is digestion rate impacted by what else you consume with the protein, similar to how eating some fat along with a starch blunts the post-prandial glucose spike?

  6. A few years ago I started taking HMB, which I believe improved my muscle gains, especially in muscle groups that I historically was a “hard gainer.” I also recently have seen some social media posts on the positive impact of HMB on muscle as we age. Have you looked at any of the research on HMB?

  7. Hi Peter,
    Would it be ok to drink 3 x 30g protein shakes daily, rather than eating food?

  8. I am reading Dr Greger’s latest book wherein he quotes numerous sources that indicate that animal protein is life shortening. He states that if you must take protein it should be plant based. Being a great fan of yours, I am confused. HELP an engineer wondering how there should be such basic different opinions.

    Tom Gessner

  9. Your push for such a massive amount of protein intake seems to me to be based more on an academic guesstimate of what is ideal and not science it self. I would be willing to bet that very few if any of the current centenarians get much more than the current daily recommended dose, especially those cultures highlighted in the ‘Blue Zone’ book which their diet lean towards more plant base with a small amount of animal protein. Then you have the the 7 Day Adventist group in CA which are vegan community and not eating any animal protein and living long and well. Michael Easter recently wrote about the Tsimani diet where this indigenous Amazon people live long and healthy lives on a simple diet that is not high in animal protein. How do you account for these wide variety of different cultures who live long and healthy lives without taking in a gram of protein per pound a day?

  10. I second Marius’s question above, with slight modification. How about 30g 2x and only one meal?

  11. Nutritional labels don’t tell us which amino acids are in our foods. Is there an easy way to look this up?

  12. Does the 1g/lb of body weight recommendation stay the same for someone trying to maintain lean muscle mass but have 50+pounds of body fat to lose (as determined by DEXA)?

  13. I am always surprised that in your discussions of animal and plant-sourced proteins you never include soybeans. Non-GMO whole canned soybeans are widely available, as well as their minimally processed products, plain (unsweetened) soymilk, and tofu. Most supermarkets (on the west coast at least) carry them, and they are an ancient food–we have centuries of knowledge about them. Complete protein. Soymilk and tofu are easily digestible. This seems a blind spot.

  14. I have followed a lowCarb diet since 2015, and have been pleased by the results. I originally was persuaded to do this because I was transitioning from marathon running when I would run out of fuel at 3.5h and was intending to compete in Ironman events. I used to be a physician and “knew” that low carbohydrate diets were dangerous etc etc. Oh how wrong I was! Anyway, I made the dietary transition successfully, and was pleased by not having to fuel in mid race during long events like Ironman (I finished an Ironman in 2018), but on further research was very impressed by the metabolic benefits of not continuing the Standard American high Carb diet. I am 50kg and try to limit my Carbs to 30-40g/day. Shooting for 1.25g – 1.5g protein/kg, I generally consume 60 – 80g protein daily in 2 meals, noonish and about 1700h.

    To follow your recommendations to approach 2g/kg I would need to increase my protein intake, but when I get to 90-100+ gm protein daily, I find I lose my ketone production, despite adhering to a daily 30g Carbohydrate limit. It seems that if I exceed what I need for Muscle Protein Synthesis (and enzyme and other protein replenishment), then the conversion of the excess protein by de-amination to Carbohydrate scuttles my ketogenic strategy. I run about 30k a week, bike some, swim some, so I’m pretty active, and there seems to be no way to follow your high protein strategy and stay in even mild ketosis.

    BTW it’s my 76th birthday today. I downhill skied hard all of yesterday at -18 degrees C, and this morning swam 1k, did 1.5h weight training, and ran 3 miles at 7.5MPH on the treadmill (got a 10k race coming up on St Patrick’s Day). I’m hoping to do OK in the Centenarian Event.

  15. If insufficient leucine limits a meal’s MPS signaling, requiring more food in order to reach the threshold, then I’m tempted to take leucine pills with my leftover drumstick, to allow this smaller high-protein snack to trigger MPS with fewer calories. How’d that be?

  16. This has already been asked, but I’ll add my voice too: for those of us who find it’s just too much food volume, can we substitute some of the protein with a free-form amino acid supplement, and in what amount?

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