I just adopted a 3 yr old great dane. He is about 20lbs under weight for his size and I want him to be a healthy weight. The problem is he won't eat dog food. The org. I adopted him from mixed wet & dry food and she said he wouldn't even eat that consistently. According to the org.'s vet he is healthy and update with shots, etc (excpet for being underweight). He will eat dog treats, bread, crackers and peanut butter. I don't know what the people before fed him. He doesn't seem to expect people food. I haven't talked to my vet yet as I just got the dog and need suggestions until I take the dog to him.

Great Dane Lady | Dog Health, Food, and Training Information

Also here is the ASPCA's dog care guideline that gives their recommendations on feeding dogs also make sure to look at the list of foods that a dog should never be given. ASPCA: Dog Care

Ask a specialist what kinds of food to use and keep in mind to make sure your dog gains weight slowly at a constant rate. If he gains weight too fast, his body might try to burn the calories off faster. Good luck!