Protein MD focuses on using nutrition to prevent or slow the ravages of aging and diseases like obesity, diabetes, cancer, and Alzheimer's.
Nonhuman animals evolved an appetite to eat an amount of protein that optimizes fertility, permitting their species to bear and raise maximum numbers of offspring. Yet these animals live longer when fed less protein than this. In other words, the amount of protein their appetite drives them to eat shortens their lives. Why would this not be true of humans?
Evolution has had little reason or opportunity to preserve human health, and possibly extend lifespan, by selecting for (a) individuals who eat just enough protein for bodily growth, repair, and reproduction, over (b) those who chronically eat excess protein, especially after age 30. This is for two reasons:
(1) Higher daily consumption of dietary protein than needed, with few breaks, may be a recent phenomenon, becoming prevalent not only after farming and animal husbandry started about 10,000 years ago, but also with the availability of processed foods over the last 100 years. Significant genetic changes in a population usually take longer to occur, although heritable epigenetic changes (e.g., changes in DNA methylation patterns) induced by the environment can happen faster.
(2) Effects of eating excess protein with no breaks, in accelerating aging and promoting certain diseases, become manifest mainly during people's postreproductive years, too late for natural selection and sexual selection to operate.
James W. Hill, MD, is a physician trained in internal medicine and radiology and a partner in the law firm of FisherBroyles.
This blog does not give medical advice. Please get your doctor's OK before trying anything you read here.
protein.md 
I wish you would post again. Particularly to comment on the resent study by Valter Longo http://www.sciencedaily.com/releases/2014/03/140304125639.htm