My normally well behaved lab has decided to start stealing food? She's 2 1/2 and has not done this since she was a pup. In the last week she has done a bit of counter surfing , woofed down half of a family sized rhubarb crumble and today she has pinched the pizza my grandson left on the table whilst he popped to the loo. Anyone have any idea's what we can do to stop this getting worse?