Here is a recipe I found for key lime pie that is virtually fat free!!

1/4 cup water
1 pkg. (4 serving size) sugar free lime gelatin
2 containers (6 oz. each) fat free key lime yogurt
1 tub (8 oz) fat free Cool Whip
1 reduced fat graham cracker pie crust

In a microwave safe measuring cup, heat water until boiling. Whisk in gelatin until dissolved. In large bowl, whisk together gelatin mixture and yogurt. Fold in topping. Carefully spread pie crust. Refrigerate 4 hours or until set.

Enjoy!