Toto is 15 months and our vet says she should only be eating about 1/4 cup, total, a day! Seems like such a small amount, but she only weighs 4 lbs. so I guess it's more than it seems. She also said that when she has a picky eater that she makes a dish comprised of ground turkey, veggies and pasta and they love it. I have made this for Toto and she gobbles it up [my husband liked it too!] He usually tastes of most everything that we feed her!!
NEVER give them any onion or spices!! I found that adding a little parm cheese, sour cream or cream cheese helps [all low fat]. In fact, she loved it so much she had to be forced back to her dog food because she gained too much weight!!
We give her vet formula Nutri-Cal every day to insure she has all the vitamins and nutrients she needs. She is a very picky eater ... the dog food that she will eat is Natural Balance [I cut it in tiny little pieces and add a little sour cream, etc. It comes in a roll similar to summer sausage] and Royal Canin Yorkshire 28. Our vet assures us that as long as there isn't any physical problems ... they WILL eat when they get hungry and we have found that to be true!! [Darn it!]
Probably the best thing is to speak with your vet about it.