When dogs are in a pack, they have a pecking order, and your puppy for the first weeks of its life will have had the protection of its mother, and her ranking.
When puppy enters your pack, i.e. your family, you must ensure that puppy knows his place in the pack’s ranking order, your family. Puppy must therefore learn that all humans are higher ranking than it is.
The last thing you want is for your dog to start playing boss, starting to protect what it considers to belong to him, i.e. “its” food, “its” toy or “its bed. The last thing you want is to be bossed around by a dog who thinks he is in charge.
What steps can you take to prevent this happening?
You eat first - this is exactly what would happen in a pack, the alpha dog/bitch eats first. Feed your dog at a set time each day - preferably a quiet time. Make your dog wait quietly for their food. Ensuring they are in the sit position. Place food in the bowl. Hold the bowl in front of the dog and place it up to your mouth and pretend to eat. To ensure also that the dog recognises you as the pack leader has eaten, lightly spit in the bowl on the food. Still ensuring your dog is sitting and calm, place the food down on the floor - holding on to the bowl. Do not allowed him to eat until you say so. Remove the food bowl once he has finished and walks away.
Do not feed at the food table, this breaks the pack code.
Repeat this until you feel confident that your dog knows that you are in charge.
I hope this helps you understand how your dog thinks, and by understanding you can help him. He is just acting out his natural instincts. Help him re-focus and establish his true order in the family. The family pet.