I have her on Natural Balance Ultra- the reduced calorie blend, currently still mixed with some of her old dry food (I think beneful), so as to not shock her system too much. I also have little 3 calorie treats (I think it's called Charlie bear or something like that?)
Pugs don't need reduced calorie/low fat foods to lose or maintain weight. They need a food with high quality protein and fat as that is what their body is designed to digest and use for enery. Natural Balance Ultra Reduced Calorie is a bit low on the protein side - 18% and 8% fat so the remaining 64% (moisture taken out) can be considered (mostly) filler. To have more than 3X "filler" in a dog food than "protein" is not ideal.