I started fasting for 16 hours at a time, with an 8 hour eating window (16:8). Actually, I wasn’t technically fasting when I started, because I’d drink a “bulletproof” (fatty) coffee in the morning. This means I’d have coffee with heavy cream or coconut oil — or both — but with Stevia instead of sugar. I also added a little cocoa powder and cinnamon. So delicious!
Anyway, the point was, I didn’t have any solid food, and the vast majority of calories that I consumed were in the form of fat. This encouraged my body to burn fat, not glucose (sugar). After 16 hours, I’d eat solid food; again, mostly fat. The idea is simple: if you eat mostly fat (70-80% of calories) your body is like, “cool, let’s burn this fat instead of storing it.”
So, I wasn’t really hungry when I started, and if I was, I had more heavy cream and coffee. After a few months of this, my body became “fat adapted,” meaning I was using using fat, not sugar and carbs as my primary fuel source. Then, I really didn’t feel hungry because I could easily burn stored fat too. I also got used to the idea of not eating in the morning. So then it was easy to stop adding the cream to my coffee, but to just have it black (still with Stevia, though).
Then, I focused on extending my fast, to 17, 18, and now 20 hours, with no calories except for the 10 or so in my coffee. Once I got to a 20 hour fast, the weight started coming off, although that’s also when I got serious about tracking what I ate. But, before I started losing weight, I noticed I was feeling much better all around.
So, @TwicePretty, in my experience, if you go right to 20+ hours of fasting, you will probably feel very hungry. Start with something you can do every day, maybe 12 hours. If you spend 7 – 8 hours sleeping, that’s easy! Then just focus on stretching your fast out when it feels good. I use an app on my iPhone called Zero (it’s free) that helps me track my fasting times each day. There are similar apps for Android. I find tracking my fasting really helps.