Bring multiple premade meals that you plan ahead. Let's say you get up at 6. Here's what I would do:
Breakfast - 6AM
Meal in the middle of class - 9AM
Lunchbreak - 12AM
Meal when you get home - 3PM
If you really had to, you could make the meal in the middle of class a protein bar. I eat one protein bar per day, which I save for a time when stuffing down an entire healthy meal isn't practical or easily done.