I have a nonstop headache. could this be due to poor diet?

Possibly: Chronic headaches are caused by factors such as food sensitivity, stress, and hormonal shifts such as with menstruation and menopause. The vast majority of chronic headaches in someone who is otherwise healthy will be due to stress. Some foods are known to trigger migraine but it depends on an individuals sensitivity to these foods. Consult a headache specialist to diagnose your type of headache.

ER: I dont think poor diet would cause non-stop headaches. It could mean an underlying medical condition or a headache disorder. Constant headache should be evaluated right away with your pcp or er.