I’ll give you my thoughts.
For the most part I personally feel fasting shouldn’t be completed until you are fat adapted (3-4 months) into doing the keto diet. You want to give you body time to get used to using fat as it’s preferred source of energy everyday.
I didn’t start doing Intermittent fasting until at least that time frame. Again this is just my person view. I would ask what have you been eating on a daily bases. How have you been feeling as well.
While the keto sticks can be a great tool for the first month or two, as you become fat adapted you will start to see the sticks not change as much as they once did. However, if you are keeping your carbs low ( me under 20 grams per day) you are now becoming fat adapted and this is ultimately what we are after.
If you do want to fast I would certainly start with some intermittent fasting (IF). Generally, you would do about 18 hours in between meals.