Just as the Donguibogam emphasized the harmony of the five flavors, modern medicine demonstrates how an excess of certain nutrients harms the body. A prime example is fructose. Fructose is the simple sugar responsible for the sweet taste in fruit, yet the body metabolizes it quite differently from sucrose or glucose.
Most sugars can be used for energy by various cells throughout the body, but fructose is processed almost entirely by the liver. While glucose elevates blood glucose and prompts insulin secretion to deliver energy to cells, fructose travels straight to the liver without causing an immediate rise in blood glucose. Although this might sound advantageous, it leads to serious metabolic consequences.
When flooded with excess fructose, the liver readily converts and stores it as fat. This pathway is known as de novo lipogenesis. When fructose intake is consistently high, fat accumulates within the liver tissue. When fat makes up more than five percent of the liver's weight, it is classified as non-alcoholic fatty liver disease.
The damage does not stop there. As fatty liver progresses, it can trigger inflammation in hepatocytes, developing into non-alcoholic steatohepatitis. This condition can advance to liver fibrosis, liver cirrhosis, and even liver cancer. Furthermore, fructose does not effectively trigger leptin, the hormone that signals fullness, nor does it suppress ghrelin, the hunger hormone. Drinking fructose-dense beverages often fails to provide satiety, creating a cycle of ongoing cravings.
Fruit juice is particularly problematic because the dietary fiber is stripped away, leaving fructose concentrated in a liquid state. This is absorbed rapidly, placing a sudden metabolic load on the liver. Overconsuming fructose not only threatens liver health, but also raises insulin resistance, increases the risk of diabetes, and contributes to metabolic syndrome through visceral fat accumulation and hypertension. A glass of fruit juice, often viewed simply as a sweet refreshment, can place a heavy burden on the body over time.
