For stealing food make sure all food is Inaccessable at all times. Everyone in the house must put on a united front and be utterly vigilant about putting food away, putting it at the back of the work tops, or if he steals from the work tops then away in the fridge or cupboards that he can't get into.
As for begging I would make sure he ADORES his bed. Have you got a clicker? Work on the 'in your bed' command, or whatever you want to call it. Every times he goes in his bed, treat ( or click and treat) .If do this enough times eventually he should zoom into his bed.
When he's doing this I would wait until you are eating and get him to go to his bed. Then, while he's in there I would frequently to start keep giving him treats. If he gets out then give him the command to go back and the treat away.
Eventually he will get the idea that while you are eating and so long as he is in his bed then he gets treats. Eventually you can wean off the treats at every meal and then he is working on the assumption that he MIGHT get treats if he stays in the bed. Obviously all this work will be undone if you feed him at the table or award him for begging.
If you do this while you are eating then eventually he will go into his bed of his own accord when you eat as that's when treats happen.
It worked for us. As I type I have two children eating and a dog sitting on the other side of the room in her basket watching with half an eye if any treats might be forthcoming.