Pre-20th century: Most people ate a diet low in carbs and high in animal fats. Heart disease and diabetes are almost non-existent.

Have to take issue with this. You have to go back to hunter/gatherers for this claim. With the adoption of agriculture and the rise of settlement the human diet went crazy for grains. Look, for one example, at the peasant diet of medieval England. It's virtually all bread and ale.

It's not so much carbohydrates per se that lead to inflammation and vascular/heart disease but the explosion of the use of refined sugar and some seed oils that began in earnest with industrialization of the food supply.

Pre-20th century: Most people ate a diet low in carbs and high in animal fats. Heart disease and diabetes are almost non-existent.

Have to take issue with this. You have to go back to hunter/gatherers for this claim. With the adoption of agriculture and the rise of settlement the human diet went crazy for grains. Look, for one example, at the peasant diet of medieval England. It's virtually all bread and ale.

It's not so much carbohydrates per se that lead to inflammation and vascular/heart disease but the explosion in use of refined sugar and some seed oils that began in earnest with industrialization of the food supply.