You can do it everyday if you like and don't encounter any negative effects.

Not eating after 8pm I think is a bit relative; what's most important with this type of IF is the length of the eating window. I forget if it's 6 or 8 hours (I do 6 or less), but basically you have a window of time where eating is allowed, and outside of the window you do not eat with the exception of bulletproof coffee. For example, if your eating window is 8 hours and you eat your first meal at 12pm, you should be done eating by 8pm.

The minimum recommended time for a fast is usually 16 hours with an 8 hour window, but I and other people go with a smaller window for potential hormonal and fat loss effects. There are tons of posts and literature on the topic that convey the many benefits.

If you know you will be done eating around 9pm, then you shouldn't be eating anything until 1pm. If you can go a little longer without food you may have increased benefits, but YMMV.

If you get brave enough you could try fasting until your evening meal once or twice a week. You can take some MCT Oil or even some butter in the afternoon to keep your energy up and stay satiated. Do what feels comfortable though and don't be afraid to experiment.

And a warning if you plan to use MCT Oil... ease yourself into it. 1 serving per day at first, then move to 1.5, then 2. Taking too much can result in some undesirable and quite unpleasant bathroom time.

Good luck!

I do it every day. I have 20 ounces coffee with 4 tbsp butter and 3 tbsp MCT oil every morning and do not eat until dinner with a 2 hour eating window. At dinner I eat all my protein and carbs for the day along with additional fat. I follow Perfect Health Diet food and supplementation guidelines.

I was just doing the fast without BPC, but honestly I suffered mentally. Adding the BPC in the morning was transformative. I think my brain really likes running on both glucose and ketones. I was in the ER a month ago and my blood work showed HIGH ketones so I think the MCT oil keeps some elevated level of ketone in the blood even if taking in 90 gms of starch carbs a day. My blood glucose level runs about 105 all day long. My weight has actually decreased after the addition of the 700+ calories of fat in the morning. My total calorie intake for the day usually runs between 2000 and 2300.

So far I've not had any negative issues. I will have my yearly physical with blood work next month so we'll see.

I will echo others - be careful with that much fat all at once. Accidents can happen until your body up regulates lipase to handle the fat.

I do bulletproof coffee when I feel like it. sometimes ill do breakfast instead, it depends on the fast and my mood.

As for your eating window, do what works for you. Who said by 8pm? what website? If you eat at 10pm adjust your next fast. Its about fitting it into your life. Dont stress out about times.

Check out this facebook group: Fierce. Fit. Fearless. its all Girls who IF. they follow Martin's Leangains approach. Its pretty awesome.

Keep in mind that consuming more than, I don't know, 20 calories of fat (which is easy with butter) you're inadvertently breaking your fast. I don't do butter in my coffee if I'm fasting. Also, fasted training a la ESE or LeanGains is recommended for strength training, not crazy CrossFit circuit style insanity. I think that might be too taxing.

Ketosis is only broken if protein or carbohydrates are consumed. Not fat.

I have been doing it for almost 3 weeks now and I love it. There have been about 3 days where I woke up late and ended up not doing my normal routine. But I am getting more and more used to it, and I really like the way I feel! I absolutely love the bulletproof coffee in the morning, I don't see how this would be possible without it haha. I am blogging about it here if you are interested: http://bulletproofcoffee.wordpress.com/2013/01/23/my-experience-with-bulletproof-coffee

Good luck!