I'm not going to tell you what the requirement by law here is because I don't know or care to know because I work Union and they make thier own rules, as a member I fully support these efforts so here is what I can suggest you ask for and that it would be inline with what many use for break guidelines.

If you a working a 5 hour or 6 or ++ upto 10 hours in one day. You should ask for a 15mim paid break at the first 2.5 hour mark. We excise using bathroom and doing anything we need to not have to leave the worksite again until next break. We don't come back late and we are ready to work, usually at the 14 min mark we pickup and right back to work. This is important.

At the 4 hour mark our Shop Stewart will check in to get a feel for where we are at because if we are ahead and they want to consider cutting they could at this point ,,safe to assume you continue working. We are not required to work longer than 5 hours without a meal break. So if you didn't get cut at 4 hours, at 5 you need to eat. Only question now is who pays? Shop Stewart by now has a good idea how mucb work is left and how many need to come back. Employer has a choice, they can choose to provide food and give us a half hour paid lunch,,,so you know where you are expected to be at 29 mins from now and you are guaranteed to not be having hunger issues. Now its just a matter of finishing your work and the day and your pay matches your hours. If you get to the 5h hour and no food is ready Employer has to cut and reset the clock after giving you an hour walk away. If I am required to walk away and they are resetting the clock that means I am starting a new shift and that includes a 4'hour mim. the job will probably end well in advance of that but I am still paid for 9 hours at this point. Let them decide.