My ability to deal with things drops when my blood sugar gets too low and I see the same thing with my children. Another big factor is sleep so I keep a very structured environment when it comes to sleeping and eating. Protein helps and we eat lots of hard boiled eggs, rice & beans, yogurt, & nuts. We do our best to avoid eating refined carbs and when we do eat them, we try to balance them with fiber and protein.
Since sleep is such a big issue, I don't let the kids have caffeine. We've seen some major regression in DD5's behavior this week and I think it's because we were on an overseas trip. I suspect the jet lag is a factor, so the #1 goal for this weekend is to catch up on sleep!