I'd start with "just stop eating" and then solve for any issues that pop up for you because people have a lot of different reactions. For me, I do alternate day fasting... sometimes 2-3 days of fasting in a row. I had some common issues such as not being able to sleep and diarrhea while fasting. So instead of 0 calories, I eat a bowl of oatmeal (high fibre) on my "fasting days". Also, when weight training while fasted I'd feel so light-headed I'd have to stop. But I fixed that by drinking 1 bottle of Gatorade (some calories + hydration + electrolytes) before exercise. You'll just have to find what works for you. Other patterns are 5:2 (2 days of fasting) and one-meal-a-day. Sometimes after a break from fasting, I'd get too hungry the first day back on fasting so I'd ease into it with one-meal-a-day.