Hunger claws at your belly. It tugs at your intestines, which begin to writhe, aching to be fed. Being hungry generates a powerful and often unpleasant physical sensation that’s almost impossible to ignore. After you’ve reacted by gorging on your morning pancakes, you start to experience an opposing force: fullness. But how does your body actually know when you’re full? Hilary Coller explains. Lesson by Hilary Coller, directed by Sashko Danylenko.