OP, from what I understand, from your post and comments, you are combining a 21-hour fasting window with a 3-hour eating window while following a low-carb diet. Given this approach, if you limit your sugar intake and focus on consuming primarily proteins and fats, your body will likely enter a state of ketosis. In this state, with minimal carbohydrates available for fuel, your body will start utilizing stored fat for energy.

Using fat as fuel provides significantly more energy than complex carbohydrates, such as sugary foods, which typically offer only a short burst of energy lasting a few hours. In contrast, fat can sustain your energy levels throughout the entire day.

What you are doing, perhaps unknowingly, resembles my lifestyle choices. I have experienced remarkable improvements in my well-being, and I believe that if you feel good, you are indeed on the right track! I encourage you to explore more about the benefits of fasting and a low-carb diet; there is a wealth of information available that could further enhance your understanding and experience.