Food and stress should never go together if it can be avoided. My suggestion for today is: Lighten up.
Even if you feel that you've overcome all your prejudices and fears about where, when and how children MUST eat, there might be a few lingering concerns. Let one go. Maybe let two go. One way to think about it is that they will live for a long time and what they eat this week doesn't matter much, or they won't live much longer, in which case what they eat this week doesn't matter at all.