Here's a thing. The growling sound isn't made by your stomach, and it doesn't happen because you're hungry - or at least, that part is a coincidence. Also known as "borborygmus", the noise if actually made in the upper section of the small intestine - the part of the digestive tract below the stomach.
As your intestinal muscles go to work shunting food and liquid downwards, gas is squeezed out of the food. It then rises through the liquid, making a burbling noise. When your stomach is empty, it acts as a big, resonant cavity to amplify the sound.
London lad, loving life and all that it has to offer.