Some people are able to isolate foods or situations that bring on their migraines.
For others it's not that straightforward. I've discovered I usually get a migraine if I eat dairy products, which were always part of those holiday family meals that sent me reeling. Chocolate is a trigger for me, too, so I avoid dairy and chocolate. But I get migraines anyway. Other potential migraine triggers are stress, travel, changes in the weather, dehydration, perfumes, menstruation, and birth control pills.