Acarbose blocks starch (and sucrose, to some extent) absorption. Instead of oily poop you get dry smelly gas that hopefully goes down over time. Starch & sucrose is not as big a part of American caloric intake as fat, but it can still help cut some of that out.

(Just sucrose. HFCS has glucose and fructose, which means sucrase doesn't need to work. Not a meaningful difference in most people considering how fast sucrase works, but when you block sucrase...)