One thing to think about is that for Indians back in those days fat was hard to come by as wild animals are very lean and eating just lean meat can lead to protein poisoning or "rabbit starvation". The people who killed bison for their tongues were probably after the fat in them....their bodies were probably craving it. Also the organs were probably prized for the same reason. Sugar and carbs had to be a mostly seasonal thing and what fruit and berries they had were not sweet like our hybridized versions. Fat is the other concentrated source of energy to run a human body and brain.
I think I remember accounts of Lewis and Clark's men struggling to do hard labor on a diet of deer and elk and were glad to get beaver, other rodents, and dogs from the Indians because of the fat.
Good Grease
The hunters went out with guns
at dawn.
We had no meat in the village,
no food for the tribe and the dogs.
No caribou in the caches.
All day we waited.
At last!
As darkness hung at the river
we children saw them far away.
Yes! They were carrying caribou!
We jumped and shouted!
By the fires that night
we feasted.
The old ones chuckled,
sucking and smacking,
sopping the juices with sourdough bread.
The grease would warm us
when hungry winter howled.
Grease was beautiful
oozing,
dripping and running down our chins,
brown hands shining with grease.
We talk of it
when we see each other
far from home.
Remember the marrow
sweet in the bones?
We grabbed for them like candy.
Good.
Gooooood.
Good grease.
Mary TallMountain
