Diet Coke Fatso Share definition Flag When a person of very large frame drinks Diet Coke with there meals. WFAN commentator Mike Francesia is a diet coke fatso. We all know one and laugh every time. Diet Coke Fatso by ObanaitisMan June 5, 2009 0 0 Get merch Get the Diet Coke Fatso mug. Buy Now — $32.95 See more merch