PHILADELPHIA — Ralphie fell in love with lobster at first bite. Steak too. But the pounds started creeping up. And up. In time, Ralphie’s doctor confirmed what his family already knew: At 30% overweight, the time had come for the South Philly Bullmastiff to go on a serious doggie diet. In the Keystone State, Ralphie is far from alone. Pennsylvania’s dogs are the most overweight in the country, according to a survey conducted by Veterinarians.org, a veterinarian-informed information group on pet issues. The study found that Pennsylvania dogs carry over 18 excess pounds on average. (A typical Ne…