What kind of food are you feeding her? Maybe she isn't eating it for a reason? Or maybe she is teething. If you are feeding a good quality food (Canidae, Innova, Merrick, etc.) then add *good* quality chicken broth (like Kitchen Basics or something from a box, not Swansons it has MSG and too much salt) or plain yogurt or fresh chicken or pureed carrots or other veggies. You could even smear peanut butter on it. I actually found some pumpkin butter at Trader's that has way fewer calories than PB and the dogs LOVE it! There are lots of healthy things you can mix with her food. If all else fails, just feed Merrick canned. No dog can pass up Wingaling.
If you are going to add the Iams gravy you might as well just put ketchup on her food.