I’ve taught human physiology, so I already knew about the limits of protein consumption: if you rely too much on consuming lean protein, you reach a point where your body can’t cope with all the nitrogen. Here’s a good, succinct explanation of the phenomenon of “rabbit starvation.”
Fat, especially within-bone lipids, is a crucial resource for hunter-gatherers in most environments, becoming increasingly vital among foragers whose diet is based heavily on animal foods, whether seasonally or throughout the year. When subsisting largely on animal foods, a forager’s total daily protein intake is limited to not more than about 5 g/kg of body weight by the capacity of liver enzymes to deaminize the protein and excrete the excess nitrogen. For hunter-gatherers (including Neanderthals), with body weights typically falling between 50 and 80 kg, the upper dietary protein limit is about 300 g/day or just 1200 kcal, a food intake far short of a forager’s daily energy needs. The remaining calories must come from a nonprotein source, either fat or carbohydrate. Sustained protein intakes above ~300 g can lead to a debilitating, even lethal, condition known to early explorers as “rabbit starvation.” For mobile foragers, obtaining fat can become a life-sustaining necessity during periods when carbohydrates are scarce or unavailable, such as during the winter and spring.
I’d never thought about that, outside of an academic consideration, since a) I don’t live lifestyle that requires such an energy rich diet, and b) I’m a vegetarian, so I’m not going to sit down to consume over 1200 kcal of meat (I feel queasy even imagining such a feast). But when I stop to think about it, yeah, my hunter-gatherer ancestors must have been well aware of this limitation, which makes the “gatherer” part of the lifestyle even more important, and must have greatly affected their preferred choices from the kill.
There is very little fat in most ungulate muscle tissues, especially the “steaks” and “roasts” of the thighs and shoulders, regardless of season, or an animal’s age, sex, or reproductive state. Mid- and northern-latitude foragers commonly fed these meat cuts to their dogs or abandoned them at the kill. The most critical fat deposits are concentrated in the brain, tongue, brisket, and rib cage; in the adipose tissue; around the intestines and internal organs; in the marrow; and in the cancellous (spongy) tissue of the bones (i.e., bone grease). With the notable exception of the brain, tongue, and very likely the cancellous tissue of bones, the other fat deposits often become mobilized and depleted when an animal is undernourished, pregnant, nursing, or in rut.
So a steak is dog food; the favored cuts are ribs and brisket and organ meats. This article, though is mainly focused on bone grease and its production by Neandertal hunters. I didn’t even know what bone grease is until the article explained it to me. Oh boy, it’s my first Neandertal recipe!
Exploitation of fat-rich marrow from the hollow cavities of skeletal elements, especially the long bones, is fairly easy and well documented in the archaeological record of Neanderthals. On the basis of ethnohistoric accounts, as well as on experimental studies, the production of bone grease, an activity commonly carried out by women, requires considerable time, effort, and fuel. Bones, especially long-bone epiphyses (joints) and vertebrae, are broken into small fragments with a stone hammer and then boiled for several hours to extract the grease, which floats to the surface and is skimmed off upon cooling. For foragers heavily dependent on animal foods, bone grease provides a calorie-dense nonprotein food source that can play a critical role in staving off rabbit starvation.
Skimming off boiled fats does not sound at all appetizing…but then I thought of pho, which is made with a stock created by boiling bones for hours, or my grandmother’s stew, which had bones boiled in the mix, which you wouldn’t eat, but made an essential contribution to the flavor. Those we don’t cool to extract the congealed fats, but they were there. Then there’s pemmican, made by pounding nuts, grains, and berries in an animal fat matrix, which now sounds like the perfect food for someone hunting for game for long hours in the cold. It’s one of those things which seems superfluous when you’re living in a world filled with easy-to-reach calories, but it makes sense. I’m going to have to think about that when I’m prepping for the Trump-induced apocalypse.

Examples of hammerstone-induced impact damage on long bones from NN2/2B.
(A) B. primigenius, Tibia dex., impacts from posteromedial (no. 4892). (B) B. primigenius, Humerus sin., impacts from posteromedial (no. 4283). (C) B. primigenius, Tibia dex., impact from anterolateral (no. 8437). (D) Equus sp., Humerus sin., impacts from posterolateral (no. 21758).
The main point of the article, though, is that they’re finding evidence of cooperative behavior in Neandertals. It analyzes a site where Neandertals had set up a bone grease processing ‘factory’ where hunters brought in their prey to be cut up, the bones broken apart, and then everything was boiled for hours along a lakeside. The place was strewn with shattered bone fragments! They also found bits of charcoal, vestiges of ancient fires. There was no evidence of anything like pottery, but they speculate that “experiments recently demonstrated that organic perishable containers, e.g., made out of deer skin or birch bark, placed directly on a fire, are capable of heating water sufficiently to process food”.
Not only do I have a recipe, I have a description of the technology used to produce the food. Anyone want to get together and make Bone Grease ala Neandertal? I’ll have to beg off on actually tasting it — vegetarian, you know — so y’all can eat it for yourselves.