>Kathryn,
>Really?? Wow. Where did I get the 40-30-30 recommendation
>from? I remember hearing it often in running
>circles/magazines some years ago, and it's always stuck with
>me that that was the "ideal" balance.
It comes from Barry Sear's "Zone Diet."
(Many of the 40-30-30 recommendations come from magazines that sell protein supplements, not from 'health' focused sources. Something to think about.)
From Andrew Weil's site:
http://www.drweil.com/drw/u/id/ART02705
"Make protein easy. You need only 10 to 20 percent of calories from protein each day—a modest amount. Even though protein such as meat has high status in our society, said Dr. Weil, there’s no advantage to eating more of it. “Protein puts a great workload on the body, which the burning of fat and carbohydrate do not,” he said."
Here's another source (10-15%):
http://www.indoorclimbing.com/Protein_Requirement.html
And from there: "Minimum Daily Protein Requirement: W.H.O. recommends 0.45 grams of protein per kilogram of ideal body weight per day.
Maximum Daily Protein Requirement: US RDA recommends 0.8 grams of protein per kilogram of ideal body weight per day. The UK Department of Health and Social Security is approximately the same."
Note that 1 km - 2.2 pounds.
I think the WHO recommendations are usually more reasonable that US recommendations, because they aren't influenced as much by commercial interests. Also, the US recommendations have a large safety margin built in.
Here's a quote from
http://www.annecollins.com/protein-diet.htm
"World Health Organization (WHO) Guidelines on Protein and Diet
The US RDA protein diet standards may be overestimated. The WHO Organization more conservatively puts our dietary protein needs at about half of the U.S. government minimum levels, or 0.45 grams of protein per kilogram of ideal body weight. Although differing weight standards and food sources of protein may apply."
Here's a short blurb (with lots of extraneous ads and such also on the site, so hard to follow the article in points!)from the same site:
http://www.annecollins.com/protein-needs-diet.htm
The American Dietetic Association (the group of registered dieticians) used to have a site where it was much easier to find info, and they usually recommended about 15% of calories from protein. I've been searching for this info, which I've seen before, but for the life of me, I can't find it!
Other sites (I haven't taken the time to read these all over, but I tried to choose those that have references):
http://www.notmilk.com/protein.html
http://www.exrx.net/Nutrition/Protein.html
http://www.new-fitness.com/nutrition/protein.html
(Seems like many of these sites are vegetarian/vegan info, which actually not what I was searching, but that's what comes up in searches for discussions on protein).
Joel Fuhrman, Neal Barnard, T.Collin Campbell, Dean Ornish, John McDougall and others recommend around 10%-15% of calories from protein. Fuhrman has a newsletter on his website that has some good info on protein, but I can't cut-and-paste segments of it, as it's accessible only to registered members, which I am.
This will get you off to a start, at least!