You will lose a pound if you burn 3500 more calories than you take in. This is one of the bottom lines in weight loss but whether or not you are actually burning 3500 calories varies from person to person with the same activity.
A dog can survive without eating for 14 days, procided day wouldn't be in good shape and health.
In these breeds, many dogs only live to 6 or 7 years old. Here are a few examples of medium to large breeds with potentially short lives: Many Golden Retrievers and Boxers die in middle age from cancer. Many Doberman Pinschers die in middle age from heart disease.