During your fasting window it’s water, black coffee, or tea (black/herbal). No creamers, but you can use artificial sweeteners if you want. If you want, you can have zero calorie beverages. But no food. Avoid calories.
Use a tdee calculator like https://tdeecalculator.net to get your caloric needs. For weight loss, aim to eat below your resting/maintenance number they’ll give you. For weight loss, what you eat isn’t as important as how much you eat, but aim for eating healthy foods.