I have a dog like that as well. Penny Lane (whom I adopted last May) was a stray and has a bad habit of getting into the garbage, jumping on furniture and getting into any food source that is accessable. One time she ate an entire loaf of bread that was on the counter by jumping on a chair - onto a table and pawing a kitchen towel until it moved the loaf of bread within pawing distance.

The good news about a food obsessive dog is that they are generally easy to train using food rewards. Penny Lane will do anything for a liver treat.

The bad news is that if I don't watch her intake, she would be an 80 lb dog in a 40 lb body.