Uan feels it is a waste of time to exercise because people in his family typically develop heart disease even when they are physically fit. he reasons that he cannot change fate. juan’s attitude is best described in terms of:

juan’s attitude is best described in terms of: Low health self-efficacy

Self-efficacy refers to someone's ability to achieve a specific result based on their confidence alone.
In this case, Juan really believe that he's never gonna be healthy and it created some sort of self-fulfilling prophecy that could lead Juan into that exact situation