What are we supposed to eat?
We’ve heard this debate over and over. We’re omnivores, no actually herbivores. We shouldn’t be eating meat, it’s carcinogenic. Look at our teeth. Does a baby want to hug a bunny or eat it?
Herbivores vs. Carnivores vs. Humans
It would be quite reasonable for anyone to think that since the diet patterns for all these animals are on such opposite ends that they extract energy from different sources. However, the surprising reality is that they all derive their energy primarily from fats.
Which mammals are designed to eat a high-fat diet?
Gorilla absorbs 66.4% as fat
Ruminants (ex. cows, goats) 70-80% as fat
Carnivores 70-80% as fat
Traditional human diets 60-80% as fat
Gorillas fall under a subtype of herbivore called hindgut fermenters. The plant matter they ingest ends up in the cecum and colon where bacteria ferment the fiber and convert it into SCFA(short chain fatty acids) which are subsequently absorbed by the gorilla.
Similarly, ruminant animals like cows and sheep derive energy in the same way except that the processing of fiber and carbs happens in their multi-chamber stomachs. So when time comes to absorb the nutrients there are essentially no carbs left to be absorbed. This goes to show that across all mammals, regardless of being a herbivore or carnivore, the dietary makeup is heavily weighted in fat.
Most people consume a majority of their energy intake as carbohydrates or fiber, but we lack the special hardware that herbivores are endowed with to convert those into an appreciable amount of SCFA. Few other species subsist on a diet of simple sugars, we only did so after the advent of agriculture. And ever since the 1980’s, we as a society have gone out of our way to cut fat out of our diets. Does it make sense that we have a drastically different energy composition compared to other mammalian species?
Which begs the question – are we an exception? Why is our modern diet 60%+ carbs and 20% fat? We should think carefully about what eating patterns are most natural for our species – and what food industries are trying to sell us by covertly dictating what our diets should be.
TL;DR
The energy composition of mammals are consistently fat based across the board. Which stands to reason that we should also have a similar proportion for our diet as a species.
Other Resources:
Arguments made for herbivory:
SCAVENGERS or HERBIVORES? Human Diet Explained – Dr. Milton Mills
Humans are Herbivores in Denial – w/ Science!
Papers:
English 
Chinese