Humans are instilled with a survival instinct. Our bodies are made to survive — we instinctually breathe, blink, sneeze, and even jump from the path of moving vehicles. This fact makes anorexia perplexing to many. How can people starve themselves, sometimes to the point of death, while many, if not most, others struggle to stay on a small diet?

The answer is unknown, really. Research has honed in on several risk factors for anorexia, including genetics, environment, emotional stability, and perhaps most fascinating, the brain.

The brains of those with and recovered from anorexia have subtle but impactful differences from those who have never struggled with the disorder. The brains of people with anorexia have a different reward response, react differently to feedback, and have altered serotonin pathways.