My frogs did eat much more than yours at that size and still do, but they have also become monstrous and recently, rather fat creatures. It may have something to do with the climate that you have your frog in. The temp is really important for proper digestion and there fore they have a bigger appetite. Humidity is also important, but is more for healthy skin and hydration. In the wild they will eat very little during the cooler months because they are cold blooded, and there is less blood flow to the digestive system along with the obvious lack of energy. They begin to eat like crazy in the summer, and its always summer in my frogs tank! If your tank temp is around 80 to 84F, then you might just have a frog that isn't a hog like all my big eaters. That might be better for your wallet though!