Hi Nayef,
Thanks for the question. There isn’t one answer to this. It depends a lot on how your health is to start, and what your long terms objectives are. The good news is that even after a period of fasting, the physiologic benefits last for a while after. So even those who restrict their fasting to Ramadan (if their fasting habits are in line with what was discussed in the article) will realize benefit for a while after. The more frequent, the greater the benefit up to a certain point. Now, there is no consensus in the scientific literature on what this point is (i.e. how frequently this should be done) but we do have our sunnah and the recommendations of the Beloved [saw] to guide us in this regard. He informed us in one Hadith about the benefits of fasting the “white days”, that is the 13th-15th of each month. That gives a great foundation for the frequency of a cyclic fast that is often used in scientific studies (such as the fasting-mimicking diet). He [saw] discussed ways of doing more, but this is an important place to practice moderation. We want to build habits that can last a lifetime. To figure out what you want to do, I would still urge a consultation with a nutritionist who understands fasting, time restricted eating, and ketogenesis. They can help you figure out how to still get your essentials, and how to monitor things so you can know you are in a ketogenic state. Experimentation is a very enjoyable part of this process; we just want to make sure it’s done with guidance.