Well, shit.

Turns out caloric restriction doesn’t do a whole lot for humans.  Does for mice… but we’re not mice.  We’re frontloaded as a species (which is apparently what helped us edge out the Neanderthals in the resource race), but not so severely front-loaded as mice, who won’t survive more than a year in the wild no matter how good shape they’re in, and thus need to live hard and fast if they want to continue to survive.

But they ARE finding that protein may be contributing to IGF-1, which causes a lot of the aging problem.  Given that we get most of our protein from red meat, it may also explain the “excess iron” problem most adults have in their mitochondria (which, given the way women tend to lose iron in menopause, may actually explain the lifespan difference).

So now we’re looking at .7 to .8 grams per kilogram of body weight, per day, as a possible (and possibly much more comfortable) longevity path.

I’m 6′, 180.  180/2.2 = ~81kg.  81*.7 = ~56 grams of protein per day.

Pulling this back into units I actually deal with on a daily basis… 56*.0353 = just under two ounces of protein per day.  In other words, the porkchop I just had at lunch just did it.

Serious tradeoffs, folks.  On 2 ounces of protein per day, you may be perfectly healthy (and vegans they’ve checked out doing this apparently have been).  In addition, this dovetails with some startling evidence suggesting that specific kinds of primarily vegetarian diet can be VERY good for you.

On the other hand, you’re not going to be a strength athlete on that little protein per day, and there may be variations due to genetic diversity going on, as well.  Bottom line: if you need the muscle, you’d better get the protein, but if you don’t… it’s probably a good idea to munch more veggies and less critters.

What is not explained here is the protein source, and that may count — would a low-iron protein source result in different IGF-1 levels than a high-iron source?  Fish for the win?