Cats are obligate carnivores.
They do not need to eat carbohydrates. Glucose are synthesized from amino acids obtained from meat they eat.
Humans do need carbohydrates. Carbohydrates are one of the three major nutrients along with lipids and proteins. Balanced nutrition is necessary.
If excessive amounts of protein are eaten, the excess amino acids are deaminated to produce ammonia in the liver. Toxic ammonia is safely excreted in the urine as urea.
In the ruminant digestive system, however, using ammonia and urea generated through amino acid deamination, rumen microbes synthesize amino acid and form microbial proteins. The microbial protein represents an important source of amino acids to ruminant animals.
Although fiber contained in carbohydrates can not be digested by any higher animals, in the gut microbiota of herbivore animals, it is fermented to produce short chain fatty acids (SCFA). SCFA are then absorbed into the gut cells as a source of energy.
Omnivore intestines also utilize SCFA but the amount of them is limited.
People might want to eat meats and vegetables for a well-balanced diet.
On the other hand, we know how to ferment food ingredients and enhance their nutrients. We can choose what to eat to keep ourselves fit.
It would be good to sometimes think about other animals because meat animals cannot live long to be eaten by us.
Natto (Fermented Soybeans)
Natto has long been a popular food produced by fermenting soybeans with Bacillus subtilis natto.
It is richer in Vitamin B2 and K2 than soybeans.
By fermentation umami is also enhanced.
It is really tasty!
I like to eat it with salt and olive oil these days.