Intermittent Fasting - A Primer ( Part 3 ) page 3

[pklopp]

Thanks pklopp. Gonna give this a try. However, what would you suggest for training during this 40h fast? Should I skip training (just move it to another day), go lighter on the weights, lift normally and hope I don't bonk or just take some BCAAs if I do train?

Just wondering.

It really depends on where in the fast you are. If you are within the first 24 hours, then there really is no reason to hold back at all. Keep in mind that your liver glycogen stores are more than adequate to keep glucose at nominal levels during this time. If your workout falls on the second day, then use your judgment, keeping in mind the nature of your workout.

The only serious hypoglycemic episode that I've encountered was during the latter part of a 56h fast ( I would start fasting in the evenings, and break the fast with a culturally consistent breakfast time ie, on the morning of the third day ). So, about 40h into it, I went to a circus arts class, and the instructor had us do a fairly intense met-con workout prior to the skills drills. I went seriously hypoglycemic, flushing, sweats, elevated heart rate, nausea, the works. Of course, not having trained at the tail end of a fast before, I was aware of the potential for hypoglycemia, so I had brought along a bottle of orange juice and a bag of nuts. Like an idiot, I left them in my locker in the dressing room in the basement. It was quite an adventure navigating the stairs to get to it, but ... all's well that ends well.

-PK

[pklopp]

pklopp, just wanted to say thank you for the great information. How do you feel about taking bcaas even when not training during the fast. Do you think it would mess up the normal process of fasting and how your body responds to it?

BCAAs are very similar in structure to glucose, actually. So, in many ways, they behave metabolically like glucose, functioning as an energy substrate. If you don't overdo it, again, I don't think it would matter much. Let's say you have 10g of BCAAs at some point in the fast, this is a 40 kCal infusion of energy. A complete non-event from a metabolic perspective. If it weren't, then your metabolism would be hyper-reactive and would pretty much guarantee that it would sooner or later end up with you collapsing, due to some metabolic overreaction to some trivial stimulus.

-PK

[MalPaz]

You have to be very careful with language because to define something is to limit it. That is, the linguistic framework we build around something restricts our ability to think about it. A perfect example of this is the notion of "antagonistic" hormones. Antagonism, for most of us, suggests that these hormones are at cross purposes with each other. But that is not what we mean at all. Rather, what we are trying to say is that, in general, when we sample cortisol and GH in an individual, we observe that they are inversely correlated, so when levels of one are high, the levels of the other are low. But this is a much weaker statement than "antagonism", because it allows for the existence of specific circumstances when we may observe high concentrations of both, like say, during prolonged energy deprivation.

When the body detects that there is an energy shortfall, it will do several things:

• It will attempt to reduce the amount of energy it discretionarily expends, which will necessarily impact thyroid hormones, and ultimately, thermogenesis, which is quite expensive in terms of energy consumed. So, during a prolonged fast, expect cold hands and feet, and better make sure you have a heavier blanket.
  
• It will attempt to conserve blood glucose and to do this it needs all tissues that do not require glucose to stop trying absorb it from the blood. Luckily, GH inhibits the use of glucose by the muscle. But that leaves us in the position of having lost a source of energy for muscular activity. Doubly luckily, GH is lipolytic which increases FFA availability as an alternative energy substrate for the muscles. But what about those tissues that cannot use FFAs and resulting ketones for energy? For those tissues:
  
• It will attempt to produce new glucose via gluconeogenesis. In this case, the inputs to this process are amino acids, so the body will need to find a supplier for these that does not require food. Luckily, we carry large pools of amino acids in all of our proteinaceous tissues. The trick is to liberate them, and this we achieve via the action of cortisol. So, during the course of a fast, cortisol levels increase to ensure that we can rely on gluconeogenesis as a source of glucose.

All of this is to say that actually, GH and cortisol are acting synergistically to provide the body with adequate energy from internal sources.

The cortisol belly fat connection is a marketing ploy to attempt to sell you some particular pharmaceutical or herbal cocktail that presumes to fix it. This is very similar to what happened with cellulite, which is nothing more than subcutaneous fat, but if I can sell you the disease, cellulite, then I can sell you the cures: anti-cellulite creams, exercise programs, and magic bracelets.

I am extremely fond of my proteinaceous tissues, especially my muscles. If there were some way to direct my cortisol to take some protein out of my nose, to make it more petite and button like, that would be great. Unfortunately, it doesn't work like that, so I am extremely wary of pushing my system into a situation where it will start to cannibalize hard earned muscle to keep my silly brain alive. So now, we have a tradeoff. How much muscle am I willing to give up for less subcutaneous fat? Not very much, so I advocate keeping fasting in the range of 40 hours in accordance with my priorities. If you really want to burn more fat, fast longer, realizing that you will be sacrificing more muscle tissue along the way. I do not recommend that you do this, but, it is ultimately your reality, and your decision.

-PK

that, was an amazing post

[Primal Fist]

Thanks for taking the time to write these great posts. I'm interested in extending my current 16-8 split sometimes, but I'm concerned about the effect on physical activity - I lift mon/wed/fri, am doing HIIT Saturdays and sometimes Wednesdays, and have a physical job too. I'm thinking the best time to try it would be after a post-workout meal and if I was off work the next day... I don't seem to be asking a question here, do I? I suppose what I'm asking is for your experience with such things.

[pklopp]

Wow! two minutes ago, I was wondering if you had posted part 3...

Thank you so much.

Definitely awesome! Have you considered an e-book?

Yes, I've actually considered expanding on my thinking in the form of an e-book. I'm trying to figure out how I can make that compatible with my day job, as I expect it would take quite a bit of my energy to do that.

I think that I am leaning towards expanding my online footprint in some way, maybe with a blog of my own or a website.

I'm going to make a standing invitation to you and anyone else that would care to be notified when this happens. If you would like, just send me a PM and I will make sure to notify you directly when I go live with whatever I decide to implement.

-PK

[Dragonfly]

Yes, I've actually considered expanding on my thinking in the form of an e-book. I'm trying to figure out how I can make that compatible with my day job, as I expect it would take quite a bit of my energy to do that.

I think that I am leaning towards expanding my online footprint in some way, maybe with a blog of my own or a website.

I'm going to make a standing invitation to you and anyone else that would care to be notified when this happens. If you would like, just send me a PM and I will make sure to notify you directly when I go live with whatever I decide to implement.

-PK

Brilliant!

[yodiewan]

Thank you pklopp. Nice breakdown of the study. This makes me less fearful of fasting longer than the 20-ish hours that I do daily. I may try a ~40h fast on a weekend since I normally only workout during the week.

[MikeEnRegalia]

Very nice!

Here's a thought: How about eating some lean protein at the end of the fast - say in the evening? By doing so you might be able to extend the fast while minimizing the loss of lean tissue.

EDIT: Essentially it then becomes a protein sparing modified fast, like for example Lyle McDonald recommends with this Rapid Fat-Loss Handbook.

[pklopp]

Very nice!

Here's a thought: How about eating some lean protein at the end of the fast - say in the evening? By doing so you might be able to prolong the fast while minimizing the loss of lean tissue.

I try to do something very similar to that, but in the end, I think the body is smarter than you and me.

Consider this: as the fast progresses, we have seen cortisol trending up, and have concluded that this is in order to provide the necessary inputs, that is, amino acids, for gluconeogenesis. This would be a futile thing to do, unless at the same time, gluconeogenesis itself was ramped up in the liver. And of course, it is. So, at the point of peak gluconeogenesis, you eat. Now, notwithstanding the issue of the cephalic insulin response ( remember the dramatic rise in insulin based upon mere anticipation of a meal? ) either your meal causes a rise in insulin, or it doesn't. If it does, we've shunted the body into storage mode, so we've changed the hormonal makeup of the fast. If it doesn't, then unless you've eaten only fats, and we're considering lean protein here, then you've just provided a nice infusion of the necessary substrate for gluconeogenesis, and blood glucose should increase, and with that insulin, and we're back to changing the hormonal makeup of the fast.

I do see one potential way around this, and that is to eat only fats. So, maybe you could drink some heavy cream? Ultimately, though, this would be somewhat pointless. The point is to metabolize fat, so feeding yourself fat reduces the overall amount of endogenous fat that you would oxidize, and it also does not address the issue of maintaining blood glucose levels.

I guess the bottom line is that a fast consists of not eating, and there is very little you can do, short of not eating, to trick your body into thinking it has not been fed when it has. Assuming you could trick your body this way, that would be disastrous, as you might find yourself in the paradoxical position where you keep eating and eating the faux feasts while the body is in full on famine response!

-PK

[GUN5LING3R]

great thread pklopp!! Someone else asked you if you believe that this type of fasting can break thru a weight loss plateau. I have made great progress and have really leaned out. I would like to lose another 5-7 lbs. of fat. Could this be the way? Thanks again for this excellent thread.