I have the same problem. My dogs have very high metabolisms. Visa is a bit easier to put weight on, but Solo is absolutely emaciated right now and I'm not sure what to do. The vet says to just keep up what I'm doing -- he is young and eventually he will start to gain weight. I'm spending $15 a day on food just for him. I am also interested in everyone's suggestions. I'm pretty sure I've tried and done everything but I have yet to find anything that has worked for Solo.