Lucas T, the Levine et al. article sure has some gaps, the main one I believe the use of the NHANES database with a 24 hours recall. It is not reasonable that such recalls can be representative of years of dietary habits.
Also, I'm pretty much skeptical about the 65 years threshold for larger need of protein (why such precision?). Also, the low-protein group has a very small numerosity compared to the others hence carries little statistical representativity, unless the CI includes the effect of small sample size, honestly right now I can't tell that.
Pls note though that the critic by Phillips is signed by authors like Donald Layman, who are sponsored by, guess who: the beef industry, the eggs industry, the dairy industry, in a few words by the very guys who have the highest interest in selling their protein. Animal protein.
At this point I believe I should produce randomized double blind trials (if there are any) but I have no time now unfortunately, I wish I were retired or that I had no other commitments. I love to geek it out but sometimes I geek it out in too may fields. Suffice it to say that I agree in part that meat with lots of vegetables may not be unhealthy, if consumed in moderation. One of the reasons not to exceed with protein is thought to be a mechanistic one: the mTOR pathway that, if chronically amplified, might prevent autophagy and enhance proliferation whit subsequent cancer growth and degenerative disease. Nobody knows with precision the activation threshold for mTOR, unless biopsies in the relevant tissues of the individual are made and lab tests carried out to measure phosphorylation ratio of mTOR protein.
Also, do not let's forget that the RDA is not the average or median minimum requirement, is the 97.5% of the normal distribution of minimum requirements, which means that it is a number which guarantees from deficiencies almost all population (actually, a sample of n=235 people). Twice the RDA means that we are far above the possible minimum requirements measured in a sample of 235 people eating different diets from different geographical areas. But it deals with minimum requirements, not optimal ones. The issue is a complex one and to date I think it has not been solved.
Edited by mccoy, 24 May 2017 - 08:07 PM.