“You can look for external sources of motivation and that can catalyze a change, but it won't sustain one. It has to be from an internal desire.”

American fitness trainer, nutritionist, businesswoman, media personality, and author

Jillian Michaels, born Jillian Leigh McKarus, is an American fitness trainer, nutritionist, businesswoman, media personality, and author. She became widely known through television, especially for her appearances on NBC’s The Biggest Loser. She has also appeared on The Doctors, hosted and co-judged Spike’s Sweat, INC. in 2015, and starred in the E! reality series Just Jillian, which premiered in 2016. Her public work centers on fitness, health, and lifestyle, and she has built a long-running presence in popular media.