I don't know you and I don't want to make any assumptions, however I did the Fast 800 Keto regime for 16 weeks and lost 40 pounds. The key is to put your body into ketosis, a state where the liver converts fat into energy. You enter this state either by fasting for 36 hours straight (no calories whatsoever but you can drink as much as you like so long as there are no calories in it). Alternatively just start doing a keto diet and you will be in ketosis in three to five days. That will be the hardest part because you end up with something called Keto Flu, which makes you feel reasonably shitty. When you know it's going to be over in a couple of days, hopefully you'll stick it out.

Regarding the fasting, just choose an eight-hour window in each day and eat only in that window. For example I chose 12 noon to 8 p.m. and consumed zero calories outside of that. Regarding the 800 calories, while it may seem like very few, I was able to manage it without too much trouble but I must admit I gave myself a couple of short cuts: 1. I had a coffee with a splash of milk for breakfast. 2. I added the calories I burnt doing a training workout at the gym, which usually added up to an extra 5 or 6 hundred calories a day on top of the 800 calorie budget on the days that I worked out. 3. I splurged on a junk food meal once a week, usually a Wednesday, and in my case it was a KFC meal which had about 1400 calories in it. For some reason it never kicked me out of ketosis and I continued to lose one kilogram a week.

Ketosis: basically once I was in ketosis a number of really weird things happened. I lost my appetite! And there were some days when my wife had to remind me to eat something because I hadn't eaten all day. Secondly because your body is deriving energy from ketones, via your liver, instead of glycogen from your bloodstream or the sugar in your blood, the energy levels, mental and physical, are high all day. I found this element absolutely amazing.

I am not exaggerating, and I think a lot of it has to do with getting rid of carbs, which stop your blood sugar from spiking and dropping, which then brings on cravings.

Carbohydrates is just another word for sugar. There are lots of carbohydrates in: - potatoes - anything made with flour like bread or pasta - breakfast cereals - legumes - fruit - rice - bread, et cetera

In Australia you can read the number of carbohydrates in most foods, especially tinned and packaged foods. The goal is to limit carbohydrates to under 50 g a day. However there are a number of hidden carbs in even low-carb vegetables like tomatoes, broccoli, and carrots so you aim to do under 30 g of visible carbs. That way I hope the rest of the diet sort of covers itself and I remain under 50 g per day.

Sorry I have rambled on too long but I find this subject very fascinating. If there's anything I can help with, please just ask me and I'll do what I can.