Plants get their energy through photosynthesis, and animals get their energy by consuming plants or other animals
Energy medicine is the term used to refer to a type of medicine that focuses on energetic interactions within a biological system to establish stable equilibrium between interdependent components. Energy medicine is one of five subdivisions of complementary and alternative medicine. This branch of medicine focuses on the concept of subtle energy.
This might not be detailed enough but she can have a healthy diet and workout to keep her skinny and fit while also being healthy. I hope this helps but u might have to add more detail to your answer than what i put.