It really depends on your height, weight, activity levels and weight loss goals. To be in Ketosis you can have up to 50 net carbs a day. Mark Sisson from the Primal Footprint/Mark's daily apple believes you can have up to 50 net carbs, where many other say don't go over 20. The more you cut the carbs, the more weight you may lose.
Bullet proof coffee is a good way to add fats to your diet. It you have it in the morning, it will help you to fill full. When I have a bullet proof coffee in the morning, I often don't feel hungry until 2pm.
You can find bulletproof or keto coffee in the receipe section. The coffee I have is 1 cup of black coffee, 1 teaspoon of butter, 1 teaspoon of coconut oil, 1 tablespoon of whipping cream, 0.5 tablespoon of vanilla extract, 1 teaspoon of MCT oil. Mix all together