Do dogs have anything on their mind, other than where there next meal is coming from?

My border collie is very intelligent. he has developed his own way of communicating with my wife and i. one form of his communication is to lick his lips, when he is hungry. for months, this communication was great and cute. but now, my border collie is carrying this too far. every fifteen minutes, he will stand in front of us and lick his lips to tell us that he is hungry. he is fed twice a day with the best of dog food. so, is our border collie playing us for a con game, hoping to grab an extra meal or is he really that hungry all the time? canned dog food in the morning and dry dog food at night. any suggestions?