What is high fructose corn syrup and why is it so bad for you? HFCS and sugar have been shown to drive inflammation, which is associated with an increased risk of obesity, diabetes, heart disease, and cancer. In addition to inflammation, excess fructose may increase harmful substances called advanced glycation end products (AGEs), which may harm your cells ( 21 , 22 , 23 ).S This is why i cant drink soda at all meh dont want cancer just found out today!