Download AppThis is an educational overview rather than medical advice.
Ask about migraine and you will hear the familiar roster of triggers. Stress, sleep changes, skipped meals, dehydration, hormonal shifts, alcohol, bright light, weather. Plenty of people genuinely do have some of these among their triggers. But the science here is weaker and more tangled than the confident lists suggest, and it is worth being honest about that rather than pretending the evidence is tidier than it is.
The confound that changes everything
Here is the single most important caveat. A lot of what people call a trigger is actually an early symptom of an attack that has already begun.
The premonitory symptoms we see before a headache, things like food cravings, neck pain, sensitivity to light, and shifts in mood or energy, overlap heavily with the items people name as triggers (review, 2024). So craving something sweet and then developing a migraine can look for all the world like sugar caused the attack. In reality, the craving may have been the brain already signalling that an attack was underway. That reverse-causation trap is what makes casual trigger spotting so unreliable, and it is why careful researchers are cautious about self-reported trigger lists.
There is a second reason for caution. When scientists have tried to provoke attacks in the lab by exposing people to their supposed triggers, the results are often inconsistent. Many named triggers fail to reliably reproduce an attack under controlled conditions, which suggests that at least some of what people believe about their own triggers does not hold up.
Where the evidence is a bit stronger
Not everything is uncertain. Hormonal changes around menstruation have reasonably consistent support as a genuine influence for many people who menstruate. Disruptions to routine and sleep also come up repeatedly. There is even a recognised pattern where attacks strike as stress lifts rather than at its peak, sometimes called the let-down effect, which is a good example of how counterintuitive this area can be.
What a headache diary can and cannot do
Tracking is genuinely useful for two things, spotting patterns and supporting a diagnosis. What the evidence does not firmly establish is that tracking on its own reduces how often attacks happen. So the honest way to think about a diary is as a tool for understanding and for having a more productive conversation with a clinician, not as a treatment in its own right.
A practical, non-obsessive approach
Track your ordinary days too, not just the bad ones, because you need a baseline to compare against. Look for triggers that repeat across many attacks rather than reading meaning into a single coincidence. Stay skeptical of anything that could just as easily have been an early symptom of the attack itself. And resist the urge to shrink your life chasing triggers that may not even be real, which tends to add stress without reducing attacks.
The honest goal is not a long list of forbidden foods and habits. It is a clearer, evidence-grounded picture of your own patterns, which is exactly what steady, low-effort logging is good at producing over time.
Sources for this piece include the premonitory symptoms review, 2024 and the American Migraine Foundation.