Announcement

Collapse
No announcement yet.

Intermittent Fasting - A Primer ( Part 3 )

Collapse
X
  • Filter
  • Time
  • Show
Clear All
new posts

  • Hi,

    So today I had an important meeting in the afternoon and was unable/willing to eat lunch beforehand. Afterwards I had no appetite (meeting went fine, hehe) and chose to push through to dinner. Ended up with a 20-24 hour fast. It really was no issue in general. When I ate I had 1 cup of rice, 12 oz of skirt steak and a mushroom sauce made with heavy cream. It was delicious! However, I was full to the point of feeling nauseous shortly after eating. Took a little concentration to keep it down. Feel OK now, 30 minutes later. Possibly ate too fast but, uh, not ideal. Need to dial it in a little better I think. Now I am just full/satisfied. Need to figure out how to skip the nauseous step...

    Later!

    Comment


    • Originally posted by govinca
      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 interesting.

      When it comes to fasting, there is a degree of proteolysis that goes on beyond 24 hours or so, or more specifically, once your glycogen stores are depleted, your body starts to transition to using ketones derived from fatty acid oxidation as an energy substrate. During this transitional phase, there is still largely a dependence on glucose and the glycolytic pathways for energy, even in those tissues that are capable of utilizing ketones as an energy substrate.

      However, due to the fact that you have depleted your glycogen stores, the body needs to bridge the gap, and it does so via gluconeogenesis from protein ( amino acids ) sources. The amino acids that are preferentially used in this case are BCAAs. This same process is active in folks following a ketogenic diet. I have read studies ( I don't have them right at hand, unfortunately ) that indicate that BCAA supplementation in people that are undergoing ketosis does not affect the ketotic state.

      Now, many of the metabolic effects of ketosis are pretty much identical to the fasting response, so I would speculate that BCAAs would not have a significant impact on your fast, depending on the quantity you ingest, of course. However, because you are supplementing with external BCAAs, realize that you are prolonging the transition phase from glycolytic to lipolytic metabolism. This would be pretty much irrelevant to you, however, if you never fast beyond 24 hours, as fasts of this duration predominantly cycle through glycogen ... you deplete while fasting, and replenish when feeding.

      -PK
      Last edited by pklopp; 07-19-2012, 07:16 AM.
      My blog : cogitoergoedo.com

      Interested in Intermittent Fasting? This might help: part 1, part 2, part 3.

      Comment


      • Originally posted by William398
        I did my 1st 40+hr fast last week. Couldn't believe how easy the last 15hrs was. When it was time to break the fast I wasn't even really hungry, could have gone on longer. After ready the above it's a good thin I didn't.
        Pretty much every time that I break my 40+ hr fast I do so because my watch tells me that it is time, not because my appetite dictates that I do so. I actually get far hungrier for my daily meal than for my 40+ hour meal...

        -PK
        My blog : cogitoergoedo.com

        Interested in Intermittent Fasting? This might help: part 1, part 2, part 3.

        Comment


        • How long to you tend to allow for a meal eating once a day? I've been eating for 1-2 hours and done, but I see mention of 20hr fast indicating that you may snack throughout the night for the next 2-3 hours after the meal? Just curious.

          Comment


          • Originally posted by pklopp View Post
            If you recall, in part two I made the point that our goal is to get to one large meal in the evening, and to have an inter meal interval of about 20 hours.

            This 20 hours is not intended to imply that we have a 4 hour eating window. Rather, it is intended to account for the absorptive phase associated with every meal which lasts 4 - 5 hours depending on the individual. Once you absorb your meal over several hours, you enter the post-absorptive state where your metabolism, in the absence of further meals, increasingly becomes reliant on FFAs from adipose tissue for energy. As your body transitions from glucose to FFAs as an energy substrate, you may experience a dip in blood glucose levels which could induce hunger. Were you to not eat, your hunger would naturally abate as your FFA levels rise and your tissues are no longer energy deficient.

            With the above in mind, if you eat like clockwork every evening at 1:00 PM. Your are spending approximately 20 hours in the post absorptive state. Now, lets consider the eating window concept of IF and the 16/8 split. If you are typical, you will break your fast at the beginning of the 8 hour window, otherwise, you would call it a 17/7 or a 18/6 split, or whatever, to reflect when you actually began eating. So, you eat at the beginning of your window, within 5 hours or so, you begin to transition to the post-absorptive phase, you experience a momentary dip in blood glucose, and you get hungry, so, about 7 hours into your eating window, you eat again, initiating another 5 hour absorptive phase, which will terminate about 12 hours after you broke your fast. The result of this is that you will spend only 12 hours in the post-absorptive state vs. 19-20 if you were to only eat one large meal in the evening. This represents a 40% reduction in the time you spend oxidizing FFAs as an energy source, and I have no doubt that it would significantly affect the results you see.

            Again, the goal is one large meal, not an eating window.

            -PK
            Found my answer . Lots of pages in this three part series....you need to do a FAQ on your blog for this series . BTW I have visited.

            Comment


            • Originally posted by Neckhammer View Post
              Found my answer . Lots of pages in this three part series....you need to do a FAQ on your blog for this series . BTW I have visited.

              My head was starting to spin a bit, but I think I followed.... I really enjoy all this info also.
              65lbs gone and counting!!

              Fat 2 Fit - One Woman's Journey

              Comment


              • Thanks pklopp. I too have read your blog. I think that it's great, and your posts. One thing that your blog *could* have, is maybe an index or table of contents? (could that fit in the welcome, or would it make the top post take half the screen?).

                I had fallen naturally into dropping lunch, but reading through I've experimented with dropping breakfast as well this week. Except for one day when I relented and had breakfast (I was stuffed all day, and didn't feel like dinner that night).

                It's a challenge to increase my calories at my evening meal (bananas and cream are my go-to), because as you mentioned, I have found that my stomach has shrunk so it's hard to over stuff it.
                Disclaimer: I eat 'meat and vegetables' ala Primal, although I don't agree with the carb curve. I like Perfect Health Diet and WAPF Lactofermentation a lot.

                Griff's cholesterol primer
                5,000 Cal Fat <> 5,000 Cal Carbs
                Winterbike: What I eat every day is what other people eat to treat themselves.
                TQP: I find for me that nutrition is much more important than what I do in the gym.
                bloodorchid is always right

                Comment


                • One thing I do miss is my eggs since I've been eating my one meal in the evening....I think my next 24hr break fast will be a dozen egg scramble. Mmmmmmmm.

                  Comment


                  • Originally posted by magicmerl View Post
                    Thanks pklopp. I too have read your blog. I think that it's great, and your posts. One thing that your blog *could* have, is maybe an index or table of contents? (could that fit in the welcome, or would it make the top post take half the screen?).
                    You've pretty much hit upon my pet peeve with all blogs, mine included, and that is the structure / organization and lack thereof. It's not enough to just provide good content, one needs to be able to find it easily.

                    Your suggestion is interesting, and I'll definitely think about it. I have yet to hit upon a good way to deal with how to structure the content, but I am on the same page as you. Stay tuned!

                    -PK
                    My blog : cogitoergoedo.com

                    Interested in Intermittent Fasting? This might help: part 1, part 2, part 3.

                    Comment


                    • Originally posted by Neckhammer View Post
                      Found my answer . Lots of pages in this three part series....you need to do a FAQ on your blog for this series . BTW I have visited.
                      Bingo! That's exactly what I would have replied.

                      I'm working on putting together a fasting FAQ, so keep checking, and thanks for visiting!

                      -PK
                      My blog : cogitoergoedo.com

                      Interested in Intermittent Fasting? This might help: part 1, part 2, part 3.

                      Comment


                      • If you've answered this question/discussed this already, let me know and I'll do some more digging to find it.

                        Pklopp, you've given some VERY detailed and helpful physiological information on other threads, so I'm really curious to know what you think of:

                        1) IFing and women, specifically
                        2) IFing and IBS

                        1) I am a women, early 30s, with very good muscle development and a few pounds of stubborn fat to lose. I IFed for months and never noticed any change in fat loss as a result. My standard was 8/16, though I frequently did 20 or 24 hour fasts, with an occasional 40 hour one thrown in for good measure. I recently read this article: http://www.paleoforwomen.com/shatter...he-literature/ which discusses how the very limited studies that did concentrate on females and IFing showed VASTLY different effects on the females, indicating that IFing was actually a stressor and did not produce the positive health benefits that it did in the males.

                        Here is an excerpt:


                        I was struck by what seemed like an egregious sex-based oversight in that MDA post I
                        linked to above. MDA cites this article as a “great overview” of the health benefits of intermittent fasting.
                        This startled me because the article MDA cited was for me one of the strongest proponents of sex-
                        specific differences in response to fasting. This occurred in two striking areas: a) women in studies
                        covered by the review did not experience increased insulin sensitivity with IF regimes and b) women
                        actually experienced a decrease in glucose tolerance. These two phenomena mean that women’s
                        metabolisms suffered from IF. The men’s metabolisms on the other hand improved with IF across the
                        board. Recall that the review was reported by MDA as “a great overview of benefits [of IF].”

                        2) Again, I am a big fan of IFing, but it contributed to making my IBS worse, because one of my triggers is eating too much at once. Even though I love the IDEA of eating one or two huge meals per day, and I was doing that daily for months, it gave me terrible pain. Going back to several smaller meals throughout the day made me feel better pretty immediately. Even now that I have mostly healed my IBS, I have to be very careful with meal size, because if I eat too much, I will definitely get abdominal pain.
                        Last edited by BestBetter; 07-20-2012, 08:45 AM.

                        Comment


                        • Originally posted by BestBetter View Post
                          If you've answered this question/discussed this already, let me know and I'll do some more digging to find it.

                          Pklopp, you've given some VERY detailed and helpful physiological information on other threads, so I'm really curious to know what you think of:

                          1) IFing and women, specifically
                          2) IFing and IBS

                          Here is an excerpt:

                          I was struck by what seemed like an egregious sex-based oversight in that MDA post I
                          linked to above. MDA cites this article as a “great overview” of the health benefits of intermittent fasting.
                          This startled me because the article MDA cited was for me one of the strongest proponents of sex-
                          specific differences in response to fasting. This occurred in two striking areas: a) women in studies
                          covered by the review did not experience increased insulin sensitivity with IF regimes and b) women
                          actually experienced a decrease in glucose tolerance. These two phenomena mean that women’s
                          metabolisms suffered from IF. The men’s metabolisms on the other hand improved with IF across the
                          board. Recall that the review was reported by MDA as “a great overview of benefits [of IF].”
                          Quite coincidentally, I recently posted something about the very study referred to in that excerpt in another thread here on MDA. I've included the salient bits here, so no need to go elsewhere to read it. Unfortunately, in general, we are both victims of the medical research literature, meaning that it is true that the preponderance of research seems to be male biased. As a result, it is difficult for me to address female specific issues because I lack the primary research from which to do so.

                          With that said, it is my experience that bloggers tend to sensationalize research in an attempt to drum up followers. The excerpt you provided is fairly representative of this. I'm not going to address the animal studies cited, mostly because we would need to agree that rats and humans are equivalent, and I'm not prepared to do that. With respect to the human studies, though, as far as I can make out, the primary concern raised is with insulin sensitivity and glucose tolerance in women in response to IF:

                          Originally posted by Paleo For Women(PFW)
                          Heilbronn et al found that with IF insulin sensitivity improved in men (21 participants) but not in women (20 participants): after three weeks of alternate day fasting, insulin response to a test meal was reduced in men. Women experienced no significant change. “It is interesting that this effect on insulin sensitivity occurred only in male subjects,” they report. The IF regime, moreover, was not just neutral for women but was downright harmful, specifically with respect to glucose tolerance...
                          Straight off the bat we have a problem because if you click through the link to get to the study, you'll notice immediately that PFW got some fairly basic things wrong, because that particular study had 16 total participants, 8 of each gender ( see the table below ), not 41 as the above quote would have it. Maybe PFW is confused and referring to another study, but it should make you raise an eyebrow, at least.

                          Leaving that aside however, if we intend to make decisions based upon this study's results, the first thing we need to do is to make sure that the study participants were fairly representative of the general population. For instance, we wouldn't necessarily want to radically change our lifestyles based on studies where herbivorous animals were fed a carnivorous diet with resulting adverse effects.

                          Let's take a look at some of the characteristics of the subjects from the Heilbronn et al study:



                          A couple of things immediately strike me about this, and I've highlighted them above. First notice that the males in this study are pretty fat relative to the females, given that they have roughly the same body fat percentage, which is very unusual for the general population, as women tend to carry more body fat in interesting places ( for the most part )

                          The second thing that jumps out is that the males have double the fasting insulin levels of the females, and yet, they have about the same blood glucose levels. In other words, relative to the women in this study, the men are significantly hyperinsulinemic. Given that this is the case, would we not expect a different response among the men and women to an ADF intervention? Would the results have been the same if the researchers had studied hyperinsulinemic men compared to hyperinsulinemic women? How about hyperinsulinemic men vs. normoinsulinemic men? Hyperinsulinemic women vs. normoinsulinemic women? If we want those questions answered, we'll need to do the studies ourselves, unfortunately.

                          But setting all this aside, the research seems to suggest that the women cleared glucose less rapidly after the ADF regime. Why would this be the case? Well, one simple answer would be that they are adapted to oxidizing fat ( ketone adapted ) and are reserving glucose for tissues the depend on it for their survival. If this were the case, ketone oxidizing tissues would become physiologically insulin resistant, giving us the observed glucose tolerance results. This would have been a very simple thing to rule out by merely testing the subjects for ketones in the blood, but unfortunately these researchers did not do so.

                          Animal studies ( for what they are worth ), on the other hand, found that ADF, as expected, caused a doubling of ketone bodies ( aceto-acetate and beta-hydroxy butyrate ) due to increased fatty acid oxidation:

                          Also noted by Anson et al was a doubling of the plasma concentrations of beta-hydroxybutyrate in the ADF group but no change in the control group.
                          Heibronn et al also did not control for several confounding factors, including neither the subject levels of physical activity, nor their diets:

                          Subjects had different levels of physical activity, with seven being sedentary, three being moderately active (exercise one to two times per week), and six being quite active (exercise three or more times per week).
                          It is well known that moderate activity is glycolytic in nature, which means that those subjects that were "quite active" would be glucose sponges. Since we are not told by the researchers who the "quite active" subjects were, if we were to assume that they were all male, that in and of itself would be enough to skew the glucose tolerance test.

                          On each feasting day, subjects were informed that they could eat whatever they wished.
                          So we don't know what the subjects ate when they weren't fasting. We don't know the caloric intake, the macronutrient breakdown, nor the meal timing ... all of which potentially play a role in glucose clearance rates. Note, for example that a carbohydrate heavy diet predisposes one to rapid glucose clearance whereas a fat heavy diet does the opposite.

                          When all is said and done, there are significant problems with this study, far too many for any conclusion to be drawn. I would be extremely leery of basing any decision about IF on this "evidence."

                          Lastly, an extremely important point that is glossed over by PFW is that this study employed an alternate day fasting protocol. So essentially, study participants would eat one day, but not the next. Even if we were to concede that this study's results were relevant, to claim that the ADF fasting protocol is equivalent and representative of the wide variety of approaches to intermittent fasting is disingenuous, if not downright intellectually dishonest. Consider that over the course of six days, participants would eat on three out of the six days. Were the ADF protocol to be replaced by three consecutive days of fasting , followed by three consecutive days of eating, it wouldn't surprise me if we would get different results. PFW, on the other hand, seems to believe that the two protocols would be equivalent.

                          PFW goes on to reference another Heilbronn study which found beneficial benefits for both men and women resulting from ADF such as beneficial changes in HDL ( women only ) and triglyceride levels( men only ). So, both genders experienced benefits, but in different ways.

                          I would certainly agree with PFW that it would be great if we had comparative studies of the effects of various fasting protocols on both men and women. I think the so called evidence that PFW cites in support of the assertion that fasting is unhealthy for women is drivel.


                          Originally posted by BestBetter View Post
                          2) Again, I am a big fan of IFing, but it contributed to making my IBS worse, because one of my triggers is eating too much at once. Even though I love the IDEA of eating one or two huge meals per day, and I was doing that daily for months, it gave me terrible pain. Going back to several smaller meals throughout the day made me feel better pretty immediately. Even now that I have mostly healed my IBS, I have to be very careful with meal size, because if I eat too much, I will definitely get abdominal pain.
                          With respect to your IBS, please allow me to defer answering that until I get a bit more time.


                          -PK
                          Last edited by pklopp; 07-20-2012, 07:19 PM.
                          My blog : cogitoergoedo.com

                          Interested in Intermittent Fasting? This might help: part 1, part 2, part 3.

                          Comment


                          • Wow, as always, you never fail to impress! I read your response quickly, because I don't have much time right now, but I plan to re-read it a few times later today when I have some time to dedicate to understanding everything you explained.

                            Comment


                            • Originally posted by dommers
                              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?
                              I think BCAAs are pretty much a non-issue, assuming that you don't overdose on them, something which is pretty hard to do, as they taste absolutely awful.

                              BCAAs seem to promote mitochondrial health and protein synthesis in muscle tissue, so there is an argument to be made for taking them. I believe that Martin at Leangains promotes something on the order of 20g BCAAs on lifting days, 10g before working out and 10g afterwards. Even if BCAAs were to be gram for gram converted into straight up glucose with 4 kcal/g energy density, and ignoring the energy costs of gluconeogenesis, then this would represent an 80 calorie carbohydrate "meal", a trivial amount.

                              I would say take your BCAAs. At worst, you would be merely wasting your money, I don't think they would be harmful to your fasts or metabolism in general, and I'll continue under this assumption until I see some research suggesting otherwise.

                              -PK
                              My blog : cogitoergoedo.com

                              Interested in Intermittent Fasting? This might help: part 1, part 2, part 3.

                              Comment


                              • So, here's my current dilemma.

                                With a 5 hour eating window, if I eat at the beginning..I'm just not hungry against by the end.

                                Today, for instance. I ate a bowl of the Primal Texas Chili at 1pm. Now, at 6:22, I'm staring at more food that I've hardly touched, totally uninterested.

                                But I know that one bowl from early was only 3/4lbs of meat, so I'm looking at probably like 700 calories.

                                I just can't get myself to eat anything else. And its good food I've got in front of me, totally tasty. But I look at it.. and I'm just "bleh."

                                I'm just getting kind of concerned that I'm not eating enough, because I seem to be hitting around 800-1000 calories a day, as a 6'2", 315lb 27-year old male. I take some multi-vitamins, and some coconut oil..but that seems like way too little if just on the micronutrient side, though protein worries me too.

                                But I am just not hungry.

                                And I feel bad eating more just because I "know I should", because that feels like totally the opposite to what I should be doing. If I can look at food and not want it, then I definitely shouldn't be eating it.

                                But the calories I'm getting are ridiculously low.
                                SW: 324.6 ----- CW: 310
                                Primal Journal

                                Comment

                                Working...
                                X