Student or Learner
What is the definition of "Commit to be fit"?
I am not a teacher.
Googling reveals that to be a rhyming slogan used as the name of several programs designed to help people improve their physical fitness (lose weight). It relies on a distortion of the intransitive verb "commit". We normally commit ourselves to noun, not commit ourselves infinitive. The slogan involves wordplay and should not be used as a model for usage for "commit".