An employer may require you to work any hours he finds necessary. There is nothing sacred about nine to five. At a former job where 24/7/365 coverage was needed, employees worked 7-3, 3-11 or 11-7. Nor is an employer limited to 8 hour shifts - they may require shifts of any length they choose. 8 hour, 6 hour, 12 hour - the law does not say otherwise.
Federal law does not require that you receive any breaks at all; meal breaks, rest breaks, smoke breaks, any breaks. Federal law says ONLY that IF breaks are offered, breaks of under 20 minutes must be paid breaks.
Some states require both meal and rest breaks; some states require meal breaks only; about half the states require no breaks. Of those states that require meal breaks, the ONLY place in the US where an hour lunch is required, is factory workers in the state of NY. Not all employees in NY - factory workers ONLY. NOWHERE ELSE IN THE US is an hour lunch required. Some require 20 minutes; several require 30 minutes. NOWHERE in the US, with a VERY few state- and situation-specific exceptions (none of which apply here) is a paid lunch required.
There are only two states that limit the number of hours an employee can be required to work - Maine and California. And not even all employees there.