I was gonna suggest something similar to what Binka Nugget said...or, if you didnt want to do the puppy food, just get a food higher in fat. I have switched Dale to Nutro, and had tried the Giant Breed formula, but realized it had less fat in it, then the regular kind. Dale needs to put on some weight too, he was always skinny, and i am sure he will thicken up as he gets even older, but i think he needs to put on some weight now, his breeder saw him recently, and suggests an extra 10 lbs.. So anyway, i would look to see what the current % of fat is in your food, and see if you can find one that is higher...and if it means putting her on puppy food, i dont think it would be a problem...

then again, she may have been the smallest of her litter (Dale was) so she might just be on the skinnier side...however, if it gets to the point where she keeps losing, i would have her checked out...

Dale is on 26% protein and i think around 14% fat...were when he was on the Nutro Large Breed, it was like 21% Protein and 11% fat...i also occasionally add canned food to the bowl...he will eat more that way...for a large breed dog, he isnt much of an eater, never was. He probably eats 5 cups a day, but could probably eventually eat 6.