Help annoying 10 yr old nephew?

My husband and I have had to move in with my sis. I have a ten year old nephew that won't let us ever eat our dinner, snacks, w/e in peace. He's always begging for a piece of what we have. In the beggining I wouldn't mind bc I do love him but after 5 months its like "really kid don't u have parents of your own to feed you or can u make yourself a bowl of cereal" we've even had to hide our snack foods and cans of pop in our room bc 1 they either go "missing" after only a couple of days or 2 he again won't stop begging untill we give him some. My husband is getting really irritated with him especially after looking forward to eating a certain thing all day he comes home to find it either half eaten or missing. I feel really bad and I don't know ehose side to be on I love my nephew but he's not some little kid starving on the street he's got his own parents to feed him, and the begging thing is really annoying and an improper way of getting what u want. Not sure what to or how to feel about all if this