Many people who suffer from recurrent headaches find that simple changes to their diet can offer fast and effective relief. Eating small, regular meals, for example, is a good preventive measure, as skipping meals is known to cause a drop in blood sugar levels, which in turn can precipitate headaches.
If you often wake up with a headache, low blood sugar could be the culprit. Try to maintain levels by eating a snack last thing at night, and again on waking in the morning.