Dogs are like children. Discipline is a
must or you have the scenario you described. My solution for you at this point is put him outside when you're eating dinner. Yes, it seems harsh and the dog will probably cry and give you the big eyes, but you must be firm. You're not being mean, you're exercising tough love.
Dogs thrive on discipline, exercised and
earned food and affection. Right now, your dog is uncertain of his place in the pack. You have to show that you are the alpha wolf and that he will get his food from you at the proper time, not when he demands it. Hard I know, but as an owner, it's your duty.
Sessha wa rurouni, de gozaro yo.