I recently came across an article citing some old studies about protein.
"• Tarnopolsky et al. (1992) observed no differences in whole body protein synthesis or indexes of lean body mass in strength athletes consuming either 0.64g/lb or 1.10g/lb over a 2 week period. Protein oxidation did increase in the high protein group, indicating a nutrient overload.
• Walberg et al. (1988) found that 0.73g/lb was sufficient to maintain positive nitrogen balance in cutting weightlifters over a 7 day time period.
• Tarnopolsky et al. (1988) found that only 0.37g/lb was required to maintain positive nitrogen balance in elite bodybuilders (over 5 years of experience, possible previous use of androgens) over a 10 day period. 0.45g/lb was sufficient to maintain lean body mass in bodybuilders over a 2 week period. The authors suggested that 0.55g/lb was sufficient for bodybuilders.
• Lemon et al. (1992) found no differences in muscle mass or strength gains in novice bodybuilders consuming either 0.61g/lb or 1.19g/lb over a 4 week period. Based on nitrogen balance data, the authors recommended 0.75g/lb.
• Hoffman et al. (2006) found no differences in body composition, strength or resting hormonal concentrations in strength athletes consuming either 0.77g/lb or >0.91g/lb over a 3 month period."