Let's look at Intermittent fasting and help you understand the key aspects. In the 8 hour window that you do eat, you should be eating nutrient dense foods of varying amounts depending on needs. Yes these include Proteins,vegetables, fats, small amount of Carbs if required. One key aspect to remember is exercising in a fasted state not only helps turn that stored fat into energy but also enhances your metabolic function at cellular level. This has a more potent stimulus if you had reduced/no carbs consumed within your fasting time frame. Here is an example:
Eat Dinner evening prior at 7pm -eat your required calories, proteins, fats, carbs, etc. In your fasting state, go to the gym / exercise, walk, run, Cycle. In your fasting state you can drink Ketone drink Goketo, coffee, tea, some protein or just water.
Depending on your own goals, Coffee & protein intake differs from person to person. If I workout in the morning, I usually drink one scoop of protein and then continue my fast until 2pm. My schedule and plan works for me so find what works for you. EVERYONE WILL HEAR OR READ SOMETHING DIFFERENT, BUT RESULTS ARE PROVEN FACTS. So do whatever will work for you.
Also, stop comparing this with religion. I F is a choice / lifestyle. You don’t do it for a period of time. You do it for as long as you need to reach your fitness and health goals.
And for those of you who say it’s unhealthy, it’s because you don’t know how to do it and you probably were told to eat 3 meals a day growing up. So you’re probably just ignorant. Keep your mind open.