Generally speaking, for most people figures of ~ 0.8g/kg are quoted. So for a bloke of ~ 70-75kg if he were an ‘everyday joe’ on 2400 cals – you are looking at about 70-90g of protein/day. For a sportsman on 3000 cals – that would be 90-115g.
There is limited evidence that anything over 1g/lb is beneficial for anabolism and there is evidence that going too high can actually reduce the anabolic response. The problem with many bodybuilders is that we have this “more is better” or “all or nothing” ideals. If increased protein is good, then a TON MUST BE GREAT!
Various studies have shown that strength-trained athletes habitually consume protein intakes higher than required.
Once requirement is met, there is only a small capacity for storage of proteins in the body – known as the amino acid pools (intramuscular and in the blood). Once the amino acid pools are filled you don’t just ‘pee out’ the excess protein – The amino acids are then ‘deaminated’ and enter energy pathways to be used as fuel:
Daily requirements for protein are set by the amount of amino acids that is irreversibly lost in a given day.
At a cellular level, an increased requirement for protein in strength-trained athletes might arise due to the extra protein required to support muscle protein accretion through elevated protein synthesis.
Alternatively, an increased requirement for protein may come about in this group of athletes due to increased catabolic loss of amino acids associated with strength-training activities. A review of studies that have examined the protein requirements of strength-trained athletes, using nitrogen balance methodology, has shown only a modest increase in requirements in this group.
A positive energy balance is required for anabolism, so a requirement for “extra” protein over and above normal values also appears not to be a critical issue for the competitive athlete as most would have to be in a positive energy balance to compete effectively.
On a larger scale – if in deficit – lean muscle acts as a ‘store’ of obligate amino acids too – and it can and will be ‘drawn on’ if diet does not reach their requirements.
At present there is no evidence to suggest that supplements are required for optimal muscle growth or strength gain.