I put a message on freecycle asking if anyone had a stair gate to keep pup out of the kitchen, and got this back from someone . I'm amazed that someone who knows nothing about my family at all is sending me messages telling me I should give away my dog because he steals food from the table.
BEGINS
4 months of bad habits.., and your dog is not happy, neither are you.
The first lesson is training the HUMAN part of the family, before training the dog part :-)). Go to a bookshop, a public library, or Amazon.com.
Feed the dog before family meals, of course NEVER at the same place YOU have your meals. Use this moment to train him to something : sit, down, stay, come...Of course don't let him jump at the food before he has done something well.
Then have the dog stay far away during your family meals, in the garage or elsewhere.
Biting of jumping must be punished immediately, on the spot, shout at him with anger, take the dog far away from the family.
That is the price to pay to have a good and happy dog.
If you can't,or don't have time and patience, give him away, for a better future for you and the dog.
Good luck
ENDS