Re: How much protein is enough to make or improve muscule mass?

Hello Phillip,

Thank you for your question.  The body turns over about 1-2% of its protein 
per day, mostly from degradation of muscle protein.  This protein is broken 
down into the individual amino acids from which it is made and about 75% of 
these amino acids are recycled.  The remainder are broken down and 
excreted.  This amounts to about 30-40g protein a day, so the typical 
western human needs to ingest 30-60g protein per day to maintain their 
muscle bulk.   This is less than the 1.5g per lb body weight that you 
suggested but I guess that is just due to variable sources of information. 
Amino acids that are not made into proteins cannot be stored and will 
therefore be broken down and excreted so there is no advantage to eating 
more protein than is necessary for the daily building and repair of 
muscles.

Humans require some amino acids in their diets but are also able to 
synthesise a lot of the amino acids in the body if necessary.  Amino acids 
are divided into essential and non-essential amino acids depending on 
whether we need to obtain them in our diet or not.  The essential amino 
acids are the ones that we are not able to make ourselves and therefore 
need from out diet.  Many animals are able to make all of the amino acids. 
 As humans have evolved our diets have changed so that we can obtain nearly 
all of our amino acids from the diet, which reduces the need for them to be 
synthesised.  Synthesis of amino acids requires a lot of energy and it is 
the amino acids that require the most energy that we have lost the ability 
to synthesise, therefore we now need these amino acids from the diet.  If 
the body can obtain its amino acids from the diet then it is very energy 
inefficient to maintain the pathways to make the amino acids which is why 
we lost this ability, therefore we now have to obtain some of our amino 
acids from the diet.  

However it is very likely that Gorillas for example with low protein diets 
are still able to make all their amino acids and then assemble these into 
proteins to make muscle and they do not need to get the amino acids from 
proteins in the diet.  Since they have a generally herbivorous diet this 
would be very low in amino acids and they would utilise the food that they 
ingest to provide them with the energy required to synthesise the amino 
acids.  Whilst this is a less efficient means of obtaining amino acids it 
is well adapted to their diet and the habitat in which these animals live.

I hope that his answers your question and wish you luck in the future.

Dave Burton