Dogs, and even cats seem to be adept at stealing our people food anytime it is left unwatched for even a minute. But, that is just how a dogs mind works about food. If you have two dogs, and put food down, the alpha dog will eat, but if he walks away and leaves food, then the second dog will grab it and eat right away.
Since we are the alpha in the family, the dog waits to see if you are going to stop eating, and as soon as he sees you leave the food, he thinks it is his turn, and gobbles it up fast before you decide to come back.
Then we turn around, only to find our food had been eaten by our dog, and we have to put them outside to be sure the food is safe, when we are not paying attention to it.