Why might a teen who is informed about health not practice good health habits?

I would say the teen doesn't think of the consequences that not having good health habits maybe affect them in their life later on. Also maybe the parents don't encourage them to live a healthier life. 

It starts with commitment. the health and safety policy is the commitment by the employer to provide and maintain a safe workplace. the commitment of the workforce is also a necessary component.when the workplace parties sit down to develop an ergonomic approach to patient handling, they will develop terms of reference that set forth how the health and safety committee will function in approaching this problem and reach its goal of reduced injuries.in general, a safe patient handling program will involve the following steps: management approval and commitment to develop and implement a patient handling program.perform a needs analysis.create and standardize patient assessment criteria.develop decision trees to standardize actions.determine which controls are needed to implement specific tasks or patient needs.institute a "no-lift" policy, where possible.