The myth that you can only use 30 grams of protein at once does not seem to die easily. Despite multiple shots to the head, it’s like a Zombie coming back from the dead routinely.
Let’s speculate that you can not use more than 30 grams of protein at once, just for fun. You and your buddies go to a nice steak house and you order up a nice 12 oz porterhouse steak which clocks in around 80 grams of protein. You are a bad ass dude who likes his steak, so you man up and eat all of it at once as you high five your buddies upon your man vs. food completion.
Are you going to finish that?
If you can only use 30 grams, where does the other 50 grams go?
Do you see a huge steak-looking poo in the toilet the next day?
Seriously, where did the steak go? Magical steak fairies took it away?
It is a total myth that you can only “use” 30 grams of protein at once.
Hopefully the confusion will end there, but I doubt it.
I believe the confusion arises when we look at protein intake and muscle growth. It is true that the muscle building response (measured acutely as muscle protein synthesis aka mps) will max out around 20 grams of a whole intact protein such as egg (Moore dr et al.2009).
In that study, there was no statistical difference in the 20 gram vs. the 40 gram group when looking at MPS. The extra protein was oxidized (used) by the body and did not contribute to an increased rate of mps.
Looks great to me!
The myth lovers will point to that study and cry “Ah ha! I told you eating more than 20 or 30 grams of protein is a waste.” But not so fast there, protein hater.
However, another study by Yang et al. in 2012 showed that 40 grams of whey was better than 20 grams in an older population; so age may be a factor.
The Real World
This makes sense when we look at the real world too. If eating 2xs more protein resulted in 2xs the muscle growth, you can bet I would be upping my protein intake tomorrow, along with many dude brahs everywhere. But it does not work that way since the muscle growth response to protein intake is not linear and results in diminishing returns over time.
Sadly, adding in 2xs more protein will not result in 2xs the muscle growth, but this does not mean your body can’t use more than 30 grams at once. Protein is essential and serves many other functions in the body other than just making your muscles bigger.
Summary: How Much Protein At Once
Being able to only use 20 or 30 grams at once is a total myth. Protein is needed for many functions in the body besides muscle growth and repair. The amount of protein used directly by your muscles also depends on your age, with older people needing more protein.
Time to order me up a big slab of dead cow and relax.
Mike T Nelson
Yang Y, Breen L, Burd NA, Hector AJ, Churchward-Venne TA, Josse AR, Tarnopolsky MA, Phillips SM. Resistance exercise enhances myofibrillar protein synthesis with graded intakes of whey protein in older men. Br J Nutr. 2012 Nov 28;108(10):1780-8. doi: 10.1017/S0007114511007422. Epub 2012 Feb 7.
Moore DR, Robinson MJ, Fry JL, Tang JE, Glover EI, Wilkinson SB, Prior T, Tarnopolsky MA, Phillips SM. Ingested protein dose response of muscle and albumin protein synthesis after resistance exercise in young men.Am J Clin Nutr. 2009 Jan;89(1):161-8. doi: 10.3945/ajcn.2008.26401. Epub 2008 Dec 3.