Not surprised, one of my migraine triggers is a blood sugar spike (either up or down, but most often happens when I skip meals).  I imagine them as eating so many carbs as to always be on the upward or downward slope of an unhealthy spike, which explains the constant headaches and incredible cravings for shit food.  If they were to eat sensibly, many of their health issues would go away, migraines would be among the first to be affected by a change in diet.