First off @Billy7871, let me say “Welcome to the forum!”
I suppose one thing I’ve learned the last few years is that there’s no hard and fast rule that applies to EVERYONE. The human body is such a wonderfully complex creation that it’s impossible to apply one approach to eating, and in this case fasting, to everyone.
Dave Asprey, founder and CEO of bulletproof.com, discusses fasting and strategies in his latest book, “Fast This Way: Burn Fat, Heal Inflammation, and Eat Like the High-Performing Human You Were Meant to Be.”
As the name implies, the book is about fasting and all the magnificent health benefits it provides. Is it for everyone? No, and he will be the first to admit that. But it can benefit most of us, certainly, those of us who are either overweight or obese. In his book, Asprey tells his own journey into fasting and what he’s learned along the way.
“The word fasting is associated with pain, and I wanted to teach people some hacks for fasting,” Asprey says. "I also put a whole chapter in for women, because fasting doesn’t work for everyone and there is no one best kind of fasting. The evidence seems pretty clear that fasting the same way every day or every week is probably also not the best strategy.
So, how do you make it so you can fast without pain when you have stuff to do? And how do you make it so you fast with all of the emotions of fasting when you want to really dig deep and do the meditation, personal development side of fasting? Sorting through all that hasn’t been done in a book, so that’s why I wrote it."
Contrary to popular belief, fasting doesn’t have to be difficult or painful. Asprey details three fasting hacks. The first one is to increase your ketone level. As explained by Asprey, hunger hormones start shifting when your ketone level hits slightly below 0.5, which is not yet the level at which you enter nutritional ketosis. He explains:
"Ghrelin will drop at 0.38, so almost no ketones. The hunger that comes with the ghrelin turns off. But there’s also a satiety hormone, the one that makes you feel full, which is called CCK or cholecystokinin. CCK, when you hit levels of 0.48, CCK makes you feel full. So, if you can get your ketones up to that level in the morning, then you will not pay attention to food.
The first step to get your levels up is mycotoxin-free black coffee — the Bulletproof beans are that. I did the original research about this. Anything that causes inflammation is going to make you hungry because inflammation just means the electrons that should be powering your thoughts are going to create inflammation in the body. They must go somewhere.
These toxins are present in very small amounts. Coffee that has more than five parts per million is illegal to sell in China, Japan and Europe, but it gets sent to the U.S., and we wonder why we get really hungry two hours after we have coffee and why we want sugar in our coffee.
It has to do with toxins, not coffee itself. A study at UC San Diego is really interesting. They found that the amount of caffeine present in two small cups of black coffee will double ketone production.
The second way is to make the coffee ‘bulletproof.’ And what that means is, you take your mycotoxin-free beans and you add some MCT oil. The 8-carbon chain (C8) MCT is the correct one. C8 MCT raises ketones four times more than coconut oil. [Then] you [add] butter and blend it or really shake it."
Of course, some might say he just has a product to sell so don’t bother reading it, but Asprey funded research at the University of Washington with Dr. Gerald Pollack, who determined that when water is mixed with grass fed butter or MCT oil, it creates a very large exclusion zone (EZ) in the water, and this EZ is important during fasting.
When you drink regular water, your body takes the water and puts it near your cell membranes, which are made of tiny droplets of fat. Body heat warms the water, converting it from bulk water into EZ water, which your body requires for ATP production and other biological processes, including autophagy and protein folding.
(I’m not an expert, I’m just repeating what I’ve read. 
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“When you put that tiny bit of butter and the MCT oil and you blend it in the morning, the MCT is going to raise your ketone levels very meaningfully. I can always get to 0.5 with just a Bulletproof coffee. But you’re also getting this water in the form of the coffee that is already primed for your body to use it to start burning fat, to start making energy,” Asprey explains.
“This is why taking a bite of butter and drinking a cup of coffee isn’t going to do it for you. It’s a different process. And I have noticed profound differences from doing that … I have found that for women, in particular, starting out with this really helps, especially if you’re over 40.”
The book covers more strategies about fasting and losing weight, and I’m sorry if this is starting to sound like an ad for the book. I’m not trying to sell anything, but it’s just interesting to me how we can hear repeatedly “bulletproof coffee breaks a fast” when biology is so much more complex than that.
I started my keto journey in January of 2017 with a two week fast, after reading Jason Fung’s The Obesity Code. I had plenty of weight to lose and fasting this long didn’t really seem that difficult. Personally, this is not a strategy I would recommend to anyone, and sometimes I still can’t believe I went two weeks without eating. But I have found it more difficult to fast even one day in recent months. This had led me to rethink my approach, and consider other alternatives and more information.
It would be nice to simply say, “stop eating, drink plenty of water, make sure your sodium levels are adequate”, and that’s all you need to know about fasting. But I’m sorry, the human body just isn’t that simple.
Billy, I encourage you to not get hung up on this rule or that rule you heard, but try a combination of different strategies and find out what works best for you. When most of us start the ketogenic diet, we have so much fat and inflammation that simply eating low carb makes a tremendous difference; even fasting may be a breeze. As time goes on, and you lose more weight, you might realize that how you used to eat isn’t quite working out as it once did, and maybe you need to try something different.
Good luck with your research and keto journey, Billy. Please report back what you’ve learned, so we can learn from it too.
I still know that your pace is great, it’s not merely compared to the slowest ones (or the hopeless ones like me) - though it depends on your fat to lose. But even people with huge extra fat don’t always lose it like crazy. I saw 4lbs per week for a long time from a heavy one who barely ate but not everyone can pull this off and most people don’t even should try.)
Especially that we don’t even need the same amount of calories every day. We can be flexible! At least many of us can.)