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Thread: Intermittent Fasting - A Primer ( Part 3 ) page 31

  1. #301
    john_e_turner_ii's Avatar
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    Quote Originally Posted by ajm422 View Post
    This study found that after 8 weeks of eating one meal a day (20-23 hour daily fasts) participants lost fat and gained lean mass despite the researchers efforts to have them eat the same number of calories as subjects eating three meals a day. This indicates (though doesn't necessarily mean) that the one meal a day crew had increased metabolisms. This sounds very reasonable to me. So after 8 weeks of intermittent fasting, the beneficial metabolism parameters were still present. Do you think the body would adapt if subjected to a longer intervention? Maybe!
    Subjects who completed the study maintained their body weight within 2 kg of their initial weight throughout the 6-mo period. There were no significant effects of meal frequency on heart rate, body temperature, or most of the blood variables measured. However, when consuming 1 meal/d, subjects had a significant increase in hunger; a significant modification of body composition, including reductions in fat mass; significant increases in blood pressure and in total, LDL-, and HDL-cholesterol concentrations; and a significant decrease in concentrations of cortisol.

    It's interesting that there was a significant increase inb blood pressure and cholesterol. Also, the decrease in cortisol is also surprising considering that the fasting would make one think that stress levels would be increased.

  2. #302
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    Quote Originally Posted by john_e_turner_ii View Post
    Also, the decrease in cortisol is also surprising considering that the fasting would make one think that stress levels would be increased.
    The answers we get are dependent on our presuppositions. If it is assumed that eating 3-6 meals a day is natural, then it would be reasonable to assume that to eat a single meal is more stressful. But maybe everything we know is wrong?

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    I agree that much of what we know or thought is wrong. I would really like to see a longer term study, and it would be interesting to see what they consider a significant increase in BP and cholesterol.

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    Hi PK,

    Would you be willing to share a sample of your current meal plan or point me to where you may have already done so? One of the challenges I have with one meal a day is consuming sufficient quantities to feel I am getting solid nutrition. I am 6', male, and 250 lbs. Obviously I am squarely in the looking for weight loss camp. Calculators put my TDEE at 2,300 to 2,800 or so. Shooting for even 2,000 is a struggle in one meal as I get overly full. Thoughts?

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    Quote Originally Posted by john_e_turner_ii View Post
    Subjects who completed the study maintained their body weight within 2 kg of their initial weight throughout the 6-mo period. There were no significant effects of meal frequency on heart rate, body temperature, or most of the blood variables measured. However, when consuming 1 meal/d, subjects had a significant increase in hunger; a significant modification of body composition, including reductions in fat mass; significant increases in blood pressure and in total, LDL-, and HDL-cholesterol concentrations; and a significant decrease in concentrations of cortisol.

    It's interesting that there was a significant increase inb blood pressure and cholesterol. Also, the decrease in cortisol is also surprising considering that the fasting would make one think that stress levels would be increased.
    First of all, though they say they maintained body weight, the 1 meal/d diet groups lost fat mass and added lean mass. That's worth saying, because it's remarkable given there were no changes in activity.

    Here are the authors' caveats regarding blood pressure and cholesterol:

    "Although within normal values, both systolic and diastolic blood pressures were higher than baseline during consumption of the 1 meal/d diet. Experimental data for normal-weight men and women on the effects of consumption of 1 meal/d rather than 3 meals/d on blood pressure have not previously been reported. Overweight men and women showed that consumption of 1 meal/d, with caloric restriction, improved blood pressure and heart rate after exercise (22). In animal models, intermittent fasting without caloric restriction has been shown to decrease blood pressure and heart rate (15). The observed increase in blood pressure in our subject population consuming 1 meal/d may be due to a circadian rhythm in blood pressure (23). Diurnal changes may have occurred, because blood pressure measurements were obtained in the late afternoon in the 1 meal/d diet versus early morning in the 3 meals/d."

    The bold emphasis is mine. I really think this explains the discrepency and I'm a little disappointed they didn't take blood pressure measurements at both time points for both groups. Honestly, it's a 20 second, noninvasive test. C'mon, scientists...

    ...and...

    "Altered circulating lipid concentrations are recognized as risk factors for CVD (28). In the current study, we found both proatherogenic (increases in total and LDL cholesterol) and antiatherogenic (an increase in HDL cholesterol and a decrease in triacylglycerols) changes after consumption of the 1 meal/d diet. These changes appeared to be independent of the controlled diets, because dietary cholesterol and the ratio of fatty acids were held constant. Studies that have attempted to determine the effects of meal frequency on biomarkers of health, such as lipid concentrations, are inconsistent. In one experimental study, healthy men were fed either 3 meals/d or 17 small snacks/d for 2 wk; subjects consuming the 17-snack diet had reductions in total and LDL-cholesterol concentrations, whereas the concentrations did not change in the subjects consuming 3 meals/d (29). Two studies also showed that omitting breakfast has harmful effects on health outcomes related to CVD (30, 31), and another study showed that this omission may reduce risk factors for CVD (32)."

    So basically, they seem to indicate that it's tough to pin down a relationship between meal frequency and cholesterol, and although they found a relationship in this study, there are plenty of other studies that found the opposite relationship or no relationship and they don't really know why.

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    As a matter of fact; carnivorous eats far fewer meals than herbivorous, maybe a couple of times a week, while the vegetable eating crowd eat almost all the time - just take a look to the African savannah and you will understand that I am right! So depending on which of those two “lifestyles” that you think you belong to will give the answer about how to time your meals! Personally I define myself as something in between extremes, as an homo omnivorous, but I never eat any solid food in the AM anymore…

  7. #307
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    Quote Originally Posted by PrimalFocus View Post
    Hi PK,

    Would you be willing to share a sample of your current meal plan or point me to where you may have already done so? One of the challenges I have with one meal a day is consuming sufficient quantities to feel I am getting solid nutrition. I am 6', male, and 250 lbs. Obviously I am squarely in the looking for weight loss camp. Calculators put my TDEE at 2,300 to 2,800 or so. Shooting for even 2,000 is a struggle in one meal as I get overly full. Thoughts?
    Check out Pk's blog "Cogito Erg Edo" (I think therefore I eat). There is a link in his sig line. It's really well written and very informative.

  8. #308
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    Thanks Paleobird. I've been to his blog, actually read his most recent earlier today. Does he go into what I am asking about? I've read the posts but they go back some time so I may be forgetting if he covered it. If you saw it recently, please point me in the right direction.

    I should say, I do currently IF. I go from 7pm to 7pm 2-3 times a week. I do not attempt to get a massive calorie, single meal in on those days. Instead I eat a well proportioned "normal" dinner.

    Thanks again for any guidance!

    Quote Originally Posted by Paleobird View Post
    Check out Pk's blog "Cogito Erg Edo" (I think therefore I eat). There is a link in his sig line. It's really well written and very informative.
    Last edited by PrimalFocus; 05-17-2013 at 03:09 PM. Reason: Typos

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    Quote Originally Posted by Paleobird View Post
    Check out Pk's blog "Cogito Erg Edo" (I think therefore I eat). There is a link in his sig line. It's really well written and very informative.
    "Ego Edo ergo Cogito" makes more sense - "I eat therefore I think" - in Gorbags ontology is food primary to thinking, so food first then thinking - no food produces bad thinking as everybody knows...

  10. #310
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    Quote Originally Posted by dob View Post
    PK, thanks for the post and sharing our insights regarding fasting. it's really fascinating.

    I'm only speculating and thinking out-loud at this point. From the charts in your original post, there seems to be a relationship between the increase in ketones (B-OHB) and the release of fatty acids further into the fast. If you were to use a ketogenic diet to increase your B-OHB (ketone bodies) prior to fasting, do you think you could it could result in releasing free fatty acids within a 24 hour period as though you've been in a fast for 40 hours? Another way to look at the same questions. If my B-OHB levels were 1.0 in a fasted state and reached 1.8 at the end of 24 hours, wouldn't there be the potential to release peak fatty acids as though one has been in a fast for 40 hours?

    I would also be interested to see if it's possible since cortisol levels would also be at it's lower levels while using a shorter fasting period while being in ketosis. What do you think?
    You're basically on the right track, but a bit fuzzy on the details.

    Ketone bodies in the blood stream result from an increase in FFA, not the other way around. In fact, ketones are produced by incomplete beta oxidation of fats in hepatocytes. Beta oxidation requires an intermediate metabolite, oxaloacetate, to completely oxidize fats. Oxaloacetate is a product of pyruvate metabolism, which in turn is the end product of glycolysis. So, when you don't have a lot of glucose around, you also don't have a lot of pyruvate, and ditto for oxaloacetate. The end result of this is incomplete oxidation of fats resulting in higher circulating ketone levels.

    With that said, you have probably heard that ketogenic diets mimic starvation. That's all fine and well, but what exactly is meant by that? Consider that there are basically four stages of starvation.

    Stage 1 is the post prandial stage and lasts about 24 hours. During this stage your body is still heavily reliant upon glucose for energy and this is supplied from hepatic glycogen.

    Stage 2 begins when your liver has exhausted its store of glycogen, so about 24 hours into your fast. At this point, metabolism is still fundamentally glycolytic although it is starting to transition towards fat / ketone energy sources. During this transition, gluconeogenesis ramps up significantly to provide energy. This phase lasts about 48 hours.

    At about 72 hours into the fast, you enter Stage 3. In this stage, metabolism has adapted to predominantly utilize fats and ketone bodies as the basic energy substrate. Obligate glycolytic tissues still need glucose to be provided via gluconeogenesis, but the bulk of the substrate for that gluconeogenesis is glycerol from oxidized triglycerides. Overall gluconeogenesis rates are lower than during stage 2. Stage 3 is a steady state stage that can pretty much go on as long as you have fat to oxidize.

    Once you run out of fat, you enter Stage 4 starvation. At this stage, the only way to provide glucose for the glycolytic tissues is via gluconeogenesis using protein as the substrate, and weight loss is rapid and death shortly follows.

    With that as background, ketogenic diets mimic Stage 3. This means that if you fast, you pretty much get to dispense with Stage 1 and 2, and with the increased gluconeogenesis that those entail, since you're practically living in Stage 3 constantly. This is quite an advantage because Stage 2 gluconeogenesis will use some protein as a substrate, so by being in ketosis, you could theoretically maintain more of your lean mass. Not a bad outcome at all. The only complication, if you can call it that, is that you need to follow a ketogenic diet which is not something for everyone.

    -PK
    My blog : cogitoergoedo.com

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

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