Joey, the filet o fish is actually one of the healthiest burgers on the menu - more so than even the "healthy" deli sandwiches!!
Less fat and only 350 kcals a pop. Regular hamburgers are 250. Big Macs have around 490, double cheeseburgers 430. Regular fries are about 350 kcal, so a filet will set you back as much as your side order! So you can see it's pretty damned good option if you're watching what you're doing!