How much protein should one consume?

With so much talk about all the fad diets, what does one eat? Most people realize that the Standard American Diet is not optimal for our health but what is? Is the Paleo (high protein/low carb) diet best or is becoming a vegan (low protein/high carb) or somewhere in the middle.

Research appears to state whatever the interest group supporting it's preference, in other words research can state whatever one desires, with the exception that the Standard American Diet is healthy.
In March the medical journal Cell Metabolism published the latest findings using over 6000 people.
The abstract can be read here http://www.cell.com/cell-metabolism/abstract/S1550-4131(14)00062-X . For those who are not as medically savvy  a wonderful explanation was published in Science Daily. The entire article can be read here http://www.sciencedaily.com/releases/2014/03/140304125639.htm

For me the highlights from Science Daily are
"The study shows that while high protein intake during middle age is very harmful, it is protective for older adults: those over 65 who ate a moderate- or high-protein diet were less susceptible to disease"

And what is considered low, moderate or even high protein
"The researchers define a "high-protein" diet as deriving at least 20 percent of calories from protein, including both plant-based and animal-based protein. A "moderate" protein diet includes 10-19 percent of calories from protein, and a "low-protein" diet includes less than 10 percent protein."

So if someone is "middle age" what should one eat for long term health? "Longo's findings support recommendations from several leading health agencies to consume about 0.8 grams of protein per kilogram of body weight every day in middle age. For example, a 130-pound person should eat about 45-50 grams of protein a day, with preference for those derived from plants such as legumes, Longo explains"

This is also the RDA guidelines for those from 25-65 years old. A little over 1 gram per kilogram of body weight for children and those over 65.  One can use Supertracker from the USDA if one is interested. The link is https://www.supertracker.usda.gov/default.aspx

This study confirms the China Study (for an overview - http://en.wikipedia.org/wiki/The_China_Study) and the Nurses' Health Study (for an overview - http://en.wikipedia.org/wiki/Nurses'_Health_Study)  which also had large populations in the studies.

For those who are raw might enjoy this video on consuming protein
https://www.youtube.com/watch?v=fnq1dsTxgRk