What are my rights on taking lunch?
Federal law does not require that employees be given lunch breaks, but many state laws do. In California, for example, the general rule for meal periods is that no person may be employed for a work period of more than five hours without a meal period of not less than 30 minutes. However, the meal period may be waived by mutual consent if a work period of not more than six hours will complete the day's work. Unless the employee is completely relieved of duty, the meal period must be considered time worked. Also, if employees must eat on the premises, a suitable place for that purpose must be designated.
For more information on different states' laws on lunch breaks, see the US Department of Labor website.