Our brains instruct our bodies how to react to external stimulation. In people exposed to traumatic experiences the brain automatically sends messages that can limit certain gene activities. Humans have retained the automatic reflex of ancient people to traumatic experiences. Ancient men and women needed to save energy to ensure their survival under traumatic situations, and accumulating fat in their liver might have provided them with an increased chance of survival. These days, however, fatty liver disease is dangerous and, unfortunately, very common. How does trauma lead to liver fattening? We discovered the genetic mechanism that leads to accumulation of fat in the liver of mice under trauma, and a potential treatment to reduce this fat. In this research we demonstrated how research combining neuroscience and genetics can offer new solutions to evolutionarily old questions.