What is causing the mans condition

A doctor in a hospital emergency room sees an obese patient who has come into the emergency room. He was pleased to report that has been losing weight rapidly but complained that he has lost energy and is tired most of the time. During his interview with the patient, the doctor also learned that the patient is taking a self-prescribed diet pill called “DNP,” which was popular in the 1920’s and 1930’s. What is causing the man’s condition? Include “Cell Biology” level details. Hint: the ingredient in the diet pills has been affecting mitochondrial metabolism.