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Shwet Shyamal

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About Shwet Shyamal

  • Birthday 10/11/1987

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  1. Hi Dean, Thanks for your comments. c = %CR that humans should do on average (from my earlier post, with emphasis added on c : "Individual optimal BMI, B' = L^x * B^(1-x), where 0 < x < 1 depends upon what CR%, c you consider safe for humans on average"). For example, in NIA monkeys, c = 0.3 = 30% (btw, in this case average and individual CR% are same, since all monkeys are subject to same degree of restriction irrespective of their body size or fat) No, just put the value of x in equation (1). Let's say my healthy early adult non-CRed BMI = 24.5. 17.575 is the number that we got earlier (L). This is the lowest CRed BMI the thinnest of us should aim for. So by equation (1), my CRed BMI becomes = (17.575^x) * (24.5^(1-x)) = 17.575^0.8 * 24^0.2 =~ 18.78 So I should aim for a BMI of 18.78. The basic idea is to come up with a range of CRed BMI instead of a single value for everybody. Thinner folks should practice less severe CR compared to fatter folks. Their final CRed BMI will still be lower (than fatter folks' final CRed BMI), but the difference won't be as much as before. So going from non-CR to CR, we are doing a BMI conversion of [18.5, 24.5] to [L, 18.78] (why 18.78? because that's what I got just before when I put in my pre CR BMI value of 24.5) Recall that indeed we got L by taking the minimum non-CR BMI = 18.5, and applying our minimum safe CR% (=5%) on it. The reason behind such a formula is to take some kind of average, between minimum safe BMI, and your adult BMI. Higher your adult BMI, higher will be this average (which is your final goal). Now, simple average comes to mind, but the thing is that simple average doesn't "compress" the final range enough. It gives equal weightage to both numbers. And if one value is extremely large (your adult BMI, for example), the average gets extremely large. So what can we do? Geometric mean comes to mind. Geometric mean of two number A and B = A^0.5 * B^0.5, which is the same as A^x *B^(1-x) with x = 0.5 by using various values of x, you will get various final ranges. You can see that higher the value of x, close the value will be to A. So x is some kind of weight given to lowest BMI, relative to your adult BMI. When x = 0.5, both numbers are given equal weight. Finally, if we decide that the population average CR should be, say 15%, then that fixes a unique value of x. Conversely, if you decide on a value of x, the population average CR% will get fixated to a unique value. I meant that there shouldn't be much difference between our post CR routine and the routine during transition period (i.e. weight loss). I guess if one doesn't want to exercise post CR, he could still do some of it during weight loss phase. But going overboard during this transition phase only just to keep as much muscle as possible is probably not a great idea. Like you said, moderation is the key :)
  2. I wouldn't put stock in subjective feeling of being healthier. Humans have difficulty being unbiased when it concerns ourselves (recall a discussion thread some years ago in the CR email list where a lot of practitioners felt (or told they were remarked upon by others that) they were one or multiple decades younger than their biological age). Given that most of the folks haven't been doing life long CR, and given the not too great results in NIA monkeys, this appears highly implausible on face value. Now, the biomarkers indeed are a good evidence, but most of us are much more health conscious than the general population (e.g. obesity avoidance, healthy food, exercise, stress management, yoga etc). So it's difficult to guess how much of this benefit is due to CR alone. Regarding fat maintenance during CR: I became aware of this when Rodney first remarked about it, and since then this has turned out to be true in other studies (for example, check out figure 1B in wild mice study [1] posted by Michael. But note that this deals with maintenance of body mass, not just fat mass). This was also the case in one of the old time classical studies (by the likes of Weindruch or some such experimenter, year < 2000), posted by Al Pater on the mailing list within the past year, but I'll be damned if I can find it among the huge pile of emails. My empirical take on this, FWIW is this: Weight measure = BMI (if relative "fattiness" is more important during CR), or weight (if total weight is more important) Let's take BMI for illustration. Assuming 95% of healthy population lies between BMI x and y (let x=18.5, y=24.5. In reality these need to be determined from data), and assuming people with the lower BMI cutoff still stand to benefit by a little CR (let's say 5% = 0.05), then this gives lower BMI cutoff, L = 18.5 * (1-0.05) = 17.575. Let your healthy early adult BMI = B => Individual optimal BMI, B' = L^x * B^(1-x), where 0 < x < 1 depends upon what CR%, c you consider safe for humans on average ... (1) This equation means higher BMI should lose more weight, consistent with the discussion above. (I suggest c = 0.15 = ~15% based on NIA monkeys' 30% CR. Humans live longer (hence less likely for CR to be as effective), have access to better medical facilities and supplements (thus getting some of the life extension & health advantages through this means), start CR late (thus the body is less adaptable to CR stress), don't live in highly controlled, accident free, pathogen free environment (hence CR more risky)). Assuming average CR% for human population following equation (1) = CR% of the human following equation (1) with B = (x+y)/2 = 21.5 (note that this depends upon BMI distribution. Taking arithmetic mean to keep things simple. Assuming normal distribution with [mu-2*sigma, mu+2*sigma] = [18.5, 24.5] gives similar x (0.794)) => B' = L^x * 21.5^(1-x) => B * (1-c) = 17.575^x * 21.5^(1-x) =>21.5 * (1-0.15) = 17.575^x * 21.5^(1-x) => x = ~0.8 There you have it folks, a simple answer to "how much CR% should I follow?". Highly crude, but better than nothing. One last point: During CR, we want to keep as much muscle mass as possible, as much bone mass as possible, as much organ mass as possible (brain, heart, etc), and finally, as much fat mass as possible (fat is also the least metabolically expensive tissue. So you can keep a higher weight with same degree of CR). So instead of trying to game the system to keep more of this tissue of less of that tissue (which has no evidence in any of the experiments, as far as I am aware), how about we follow our usual routine during weight loss and let the body decide what it wants to keep in what proportions. By doing adult CR, we are already skewing this in favor of certain tissues (for example, your bones won't (typically) grow shorter after CR).
  3. This retrospective study was done on a very large number of metformin treated diabetics with pair matched non-diabetics. Diabetics had higher BMI, but were also more often on treatment for high lipid and hypertension. Unadjusted all cause mortality of diabetics was equal to controls (an achievement by itself), where as adjusted mortality was lower! Link to full text paper: http://onlinelibrary.wiley.com/doi/10.1111/dom.12354/full
  4. Shwet Shyamal

    Rapamycin Improves Vaccine Response in the Elderly

    Hi Michael, Have you started taking rapamycin, or thought of starting soon? If so, what dosage would you suggest? Like you and others, I too feel at this stage that rapa (and to a lesser extent, metformin) has potential, but am unsure about the dosage.
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