Plain Turkish coffee (no sugar, no milk/cream) does not meaningfully break a fast from a calorie perspective. Two caveats: caffeine can increase hunger or irritate the stomach in some people, and late-day caffeine can impair sleep and indirectly worsen appetite control. What breaks a fast is usually what you add: sugar, syrups, cream, milk, or fats that raise calories. If your goal is a clean fasting window, stick with black coffee, unsweetened tea, and water. People with reflux or palpitations may not tolerate coffee on an empty stomach and may choose a gentler schedule.