If we start with the most basic information available, then we can look at the National Academies Institute of Medicine RDI. That is the minimum amount necessary to prevent catabolism and deficiency diseases. The National Academies recommendation is 0.3 g/lb of body weight.
What about the needs of active and athletic folk, especially weight lifters?
The straightforward answer is that such folks need more protein. Multiple reviews (Campbell, et al., 2007, Phillips 2013 & 2014), including one focused specifically on females (Volek, et al., 2006), have looked at the protein requirements for optimum performance and recovery in athletic individuals. With a review of the research, they each determined that a range of 0.64-0.73 g/lb/day will cover the needs of active and athletic folks.
You can quickly find out what the range is for your body weight by entering it in the field below. Once you’ve entered your weight (lbs), hit enter.
Body Weight (lbs):
Protein Range (g/day):
Studies of serious competitive lifters/athletes (Lemon, et al., 1992, Hoffman et al., 2006) have not shown a benefit beyond the 0.82 g/lb/day. For those whose living is tied to their lean body mass and squeezing every last ounce of muscle growth out of their training, then the possibility of getting the slightest benefit from going higher is worth it. For the Gen Pop active lifter that has no financial stake in the game, we’re not likely going to notice any benefit from eating more protein than 0.64-0.82 g/lb/day.
If we did go higher, is there any concern about kidney damage or bone density loss? Not based on evidence. Numerous studies have been done with so-called “high” (Arciero, et al., 2014, Hursel, et al., 2015, Josse, et al., 2010, Layman, et al., 2005 & 2009, Lejeune, et al., 2005, Longland, et al., 2016, Martens, et al., 2015, Mullins & Sinning, 2005, Parr, et al., 2016, Soenen, et al., 2013, Thorpe, et al., 2008, Wycherley, et al., 2010) and “very high” amounts of protein per day (Antonio, et al., 2014 & 2015, Robinson, et al., 2015) without report of kidney or BMD issues. Multiple reviews on protein consumption (Campbell, et al., 2007, Hoffman, 2004, Hu, 2005, Lowery & Devia, 2009, Manninn, 2004, Phillips, 2013 & 2014, Volek, et al., 2006) have also not found evidence to support these health concerns.
Whether we’re talking about protein consumption deemed “moderate”, “high”, or “very high”, the preponderance of evidence says that getting more than the RDI will not be detrimental. It also suggests that active and lifting folk definitely need more protein than the RDI.