Why are there so many calories in Noahs Bagel's city salad?

810 calories and 68 g of fat. I slightly taken aback that there were 612.0 calories from fat in such a simple salad (containing Mixed greens, raspberry vinaigrette dressing, sugared walnuts, gorgonzola cheese) Did most of the fat come from the walnuts? (I'd say there was less than 1/3 of a cup)