So sorry to see read about your cat's losing weight. How is the cat's energy and activity level?
As they aged, my cats lost some weight, too. They were fine until they reached age 17 and 19 yr, respectively. In other words, when they went, they went from old age.
because barley is what the gladiators used to eat to put on a very dense type of fat.
Sorry for bluntness but what possible relevance does a story about a human diet have for a cat? Their metabolism and digestion is not that of a human.