I have long been troubled by the "they ate nose to tail", and all of the fatty organs. By FAR, the most common organ mentioned is the liver. Ahem. The liver is not supposed to be fatty, and I don't think these people are really so hypocritical as to eat foie gras and claim that's what they mean. Well ....
As the fauxtrage over the not-yet-released 2015 Dietary Guidelines rages on over on Marion Nestle's blog, George carries the fatty offal flag in to blame American health issues on our Orwellian fear of the fat in organ meats ... at the hands of the DGAC. Yeah, if by that he means we've been avoiding tongue, tripe and brains (classic American fare!), I guess he has a point. Actually, as you'll see, many of these meet the DGAC's definition of "lean" (< 10 grams per 100 grams weight), but are not "low fat" by percentage.
So just a little sampling of some specialty/organ meats. You can click, resize in browser, and the URLs for nutritiondata.com are included.
The concern for most of these seems to have been the cholesterol levels, which has been dropped. Still, how much liver did we used to eat? Mathematically it just can't be that much! Near as I can find from combining sources, the liver is perhaps 1% of the "meat" on a steer (~570 lbs total, 5-6 lb liver) and according to my first link, the specialty stuff totals around 5%.
I await the chiterlings craze in paleo!!!
[150 lbs/yr] x [16 oz/lb] ÷ [365 days/yr] ≈ 6.5 ounces per day
[200 lbs/yr] x [16 oz/lb] ÷ [365 days/yr] ≈ 8.75 ounces per day