Medical experts usually say the average person can live for 4 to 6 weeks without food. The amount of time someone can go without water is much shorter, roughly a week (or less).
Your employer can force you to take leave at a particular time as long as they give you at least two weeks' notice. However, it is common for employer and employee to come to an agreement about the timing of annual leave. If you put in a request for leave, your employer has to have a good reason to refuse it.
Employee Failure to Provide Notice. Foreseeable Leave of 30 Days or More. When the need for FMLA leave is foreseeable at least 30 days in advance and an employee fails to give timely advance notice with no reasonable excuse, the employer may delay FMLA coverage until 30 days after the date the employee provides notice.