If you really want to stop your dog from begging for food, you're going to need to learn to refrain from giving in to his begging every time there is food around. It is not a secret as to the reason why a dog begs, well, it is because they would like food as soon as you have food anywhere near you or as soon as you go in the kitchen. Begging isn't disrespectful or weird to your puppy; it's instinctive, so it takes a great deal of consistency to reverse that behavior if we've been reinforcing it. This begging "attitude" began a long time ago with the dog's descendants. With time, this became instinctive to wolves which carried over to dogs through their DNA. Our dogs are hard-wired to seek opportunities to get food from us and given that they're observant they quickly grasp that begging brings about payoffs when we respond to all these signals that they have gained mastery so well over time. It is one of the most common complaints of pet owners, howeve