Intermittent Fasting FAQ…

Just a quick on for you today. Given how prominently Intermittent Fasting is featured in my programs, and how often I discuss various Intermittent Fasting protocols it’s not surprising that I get a lot of questions about the practice. What’s okay? What isn’t? It’s even less surprising is the fact that the same questions get asked over and over and over again. This means, of course, that I should write a post to address these questions.

Certainly, it will help a lot of people, but my more self-serving reasons is that it would be much easier, in the future, to just send a link to this article, rather than continuing to type out the answers over and over, several times per week.

Why did it take me so long to do this? Because I’m a big, dumb animal, folks.

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Me, basically.

Anyway, if you’ve read a lot about fasting, you’ll probably know the answers to a few of these. If you’ve recently begun fasting, then you’ve probably asked yourself (or me) one of these questions, or at least been curious. Definitely check these out.

If you’re a complete neophyte to the idea of fasting, you’ll get a lot out of this article, but you really should check out the basics first. My articles Intermittent Fasting 101 & Intermittent Fasting 201 should be enough to get you started.

Finally, I just want to reiterate that this is intended to be a quick blog to save us all time, not a dissertation, or even a full article. As such, it’s not filled with science and links to PubMed.

Meaning that you might be disappointed if your general reaction to is this:


Don’t be that guy.


With all of that said, on to the questions.

On General Fasting

1) Fasting for 16/24/36 Hours Seems Hard; Like, Weawwy Hard–Will I Die?

Yes, you will die. But probably not as a result of fasting.

And, honestly, it’s not that hard once you get used to it, so just man up. I don’t mean to make light of it–your first foray into fasting can certainly bring with it a certain degree of discomfort. You’ll be a little hungry. This is normal, and it’s nothing to worry about. And, the longer your fast (as in, practice the habit of fasting, not maintain one single fast), you’ll find that you don’t get as hungry as often. And so fasting becomes much easier.

The abbreviated version of why this happens: there’s a hormone called ghrelin that controls hunger; the production of ghrelin is dependent on when you eat. (So, producing ghrelin makes you want to eat, and eating produces ghrelin…which makes you want to eat more. More than a little annoying.) Ghrelin secretion in your body happens on a schedule based on your eating schedule; meaning the more often you eat, the more often you produce ghrelin, and the more often you want to eat.

All of which explains why you’re always hungry. Fasting will be hard in the beginning, because you’ve conditioned your body to produce ghrelin on a schedule, and so you have to push through that hunger.  Here’s the good news: ghrelin secretion begins to adapt to new eating patterns pretty quickly. Fasting helps you influence this because you’re eating less often, which means you’ll get hungry less often.

Science lesson over. The upshot is that the discomfort from fasting fades quickly, and the benefits (both longterm and short term) outweigh the acute inconvenience.

Or, as I said earlier, man up.

2) But Wait! Isn’t It Bad 4 My Metabolismzz?

No, it isn’t. This a myth that I could write about all day, so, again, a summary.  The idea that not eating will slow your metabolic rate is based of the fact the eating increases your metabolic rate; the increase occurs when you eat due to something called the Thermic Effect of Feeding (TEF). Basically, you expend energy to break digest, absorb, and utilize the food you eat. This part is true.

Here’s the part that’s not true: the suggestion more often you eat, the more often your metabolism will increase, therefore not eating often can lead to metabolic slowdown. For years, you’ve been told that eating 5-6 small meals per day helps you keep your metabolism elevated. Again, not true.

The fact is that TEF is determined by your total energy intake, not how often you eat. So, it doesn’t matter if you have 2 meals or 8, as long as you’re getting the same number of calories, the effect will be the same.

All of which is to say that a daily fast of, let’s say 16 hours, does not decrease your metabolism.

On Timing

These questions comes up a lot with people who practice 16/8 fasting. In a perfect world, that model looks like this: fast for 16 hours, hit the gym, start eating. The suggested feeding window is 2-10pm; so, ideally, you train at 1pm. That’s a problem for a lot of people who have pesky things called “jobs.”

But, simply because you can’t follow that one specific recommendation doesn’t mean you can’t utilize fasting, or get great results from it. To that end, here are the two most common schedule concerns that I get, and my recommendations.

3) I can only train in the evening, after work. Should I wait until then to break my fast? 

Depends. You can wait to break your fast if the following apply to you:

  • You don’t mind eating your first meal at 6 or 7pm.
  • Your workout won’t suffer from the extended fast.
  • You won’t have an issue getting in all of your calories and macros before bed.

If those things are not an issue for you, sure, you can wait to have your first meal until after your workout. But, you don’t have to. The second option is to simply break your fast at around 1pm with a moderately sized protein rich meal, have a shake or something like a bit later one (up to you–if I eat before my workout I puke), and then have some BCAAs before training at about 5:30pm.  When you finish your workout, start eating the rest of your calories.

I’ll mention that option one is probably better suited to fat loss, while option two is better for muscle gain.


4) I can only train in the morning, before work. Should I eat after? How do I handle this? 

The obvious question here is about meal timing: if this person finished their workout at, say, 7am, they have to make a choice and either:

  • break the fast post workout, and then have an eating window of 8am-4pm. This can work, but you’re missing out on all of the nifty hormonal stuff that comes with not eating in the morning, including increased growth hormone secretion and better insulin management.
  • don’t break the fast post workout; simply continue fasting until 1-2pm. Much easier in terms of thinking. Probably better and more effective from a hormonal standpoint. But carries with it the inevitable question about wasting the post workout window. It’s a tradeoff – can’t have everything. You could also take BCAAs post workout to get some PWO anabolizmz. (More on BCAAs below).


On Breaking The Fast

5) Will XYZ Break My Fast?

I get this one a lot. People want to know what constitutes breaking a fast, and what, if any, caloric intake is acceptable.

Here’s a list of things to DO NOT break your fast:

Those things are pretty much fine in just about any quantity. Cool?

Here’s a list of grey area stuff, with a note on why gets the official rating of sometimes.

NON-BLACK COFFEE - You can add all sorts of stuff to coffee to make it either more delicious or healthier–or sometimes both. But, adding anything to coffee that has calories can potentially break your fast. A little heavy cream makes things tasty. A little coconut oil gives you some medium chain triglycerides, and you know how delicious those are (see Bulletproof Coffee).  

If you have a single cup of coffee per day, this is a non-issue; but if you need 4-5 cups to get going in the morning, and you’re adding a tablespoon of cream or coconut oil to each on, that will add up. There’s no hard and fast rule, but I say just try to keep your total caloric intake below 100, even if it’s from fat. The poison, as they say, is in the dose.

 I don’t have a problem with diet soda or artificial sweeteners in fairly limited quantities. However, not all are created equal, and they can exert different effects. For example, one of the sweeteners in Coke Zero is acesulfame potassium, which has been shown to be (potentially) insulinogenic; so that’s not the best choice during a fast, because you want to minimize insulin. Diet Coke, on the other hand, doesn’t have it. 

Is it going to make a huge difference? Probably not. Is drinking diet soda going to kill you and make you fat and give you herpes? Probably not. Still, probably best not to make it your primary liquid of choice. Again, the poison is in the dose.

 Branched Chain Amino Acids are fantastic for a number of reasons, and when it comes to fasting, most people consider them necessary. BCAAs can blunt hunger, help you build muscle and retain LBM, and allow for better workouts over all. So, why are they in the grey? 

Very simply, they’re extremely insulinogenic. The production of insulin shuts down the production of growth hormone, so dosing with BCAAs may negate some of the benefits of fasting. Whether this is actually the case is open to debate. Many experts recommend this; for example I’ve heard that the position of BCAAs not breaking a fast referred to as Berkhan’s Law, named for Swedish nutritionist Martin Berkhan, one of the godfathers of the IF movement.

My personal position is this: if you’re focused on insulin management (for example, during an Insulin Reset, which appears in Phase I of Engineering the Alpha), I would skip the BCAAs until after your workout. If you have good insulin management or are trying to gain muscle, go for it.



I’m looking to keep this post dynamic and update it as time goes on, so feel free to drop and Q’s about fasting below, and I may  steal feature them going forward.

Hopefully, this post will help you as much as I know it will help me–whether you learn from the information or just refer people to it so you don’t have to keep answering these!


Happy Fasting,


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    • Roman

      That’s actually a great plan. Well done!