Experiencing headaches while fasting is quite common, but the good news is, it can be minimised and avoided all-together. The mild to extreme headaches can be caused by a number of triggers such as lack of sleep, caffeine or nicotine withdrawals, dehydration, sunlight, and hypoglycaemia. To have a headache-free day in Ramadan, one must sleep on time, drink plenty of water, avoid addictive substances, and eat a balanced diet with low sugar content.