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 addition, humans can actually survive crazy amounts of time without any type of food, liquid or otherwise, as long as they still have adequate water. Depending on health and body size, it's estimated that a healthy person can last between 30 and 40 days without eating a single bite. In one extreme case, a 456-pound man lasted an astonishing 382 days without eating any food, solid or liquid, ABC Science reported. Over the course of his year of starvation, the man dropped down to 180 pounds and was able to keep the weight off for five years.