= 27d567bc2d48d9f40e9ccc20ea370b15)
timtyler comments on What is the evidence in favor of paleo? - Less Wrong
You are viewing a comment permalink. View the original post to see all comments and the full post content.
= 783df68a0f980790206b9ea87794c5b6)
Loading…= b715d02e85f7b3b4ae65ca3d3e450868)
Subscribe to RSS Feed
Powered by Reddit
= f037147d6e6c911a85753b9abdedda8d)
You are viewing a comment permalink. View the original post to see all comments and the full post content.
Comments (96)
Most living people don't optimise for that either. If they did, more would practice calorie restriction.
I've yet to see any evidence on the effects of calorie restriction on humans. Mice are quite different from us, and all evidence on calorie restriction I've seen was done on mice.
Also, there is no just how long you live, but also life quality. We know the brain is a massive consumer of calories. We know that when people are even in light hypoglycemia, their reflexes and cognitive abilities go down. I never saw any study on the effects of calorie restriction to attention, reflexes and cognitive abilities.
Some human research is listed here.
There are plenty of studies on that - e.g. start here.
Evidence on humans can be found through here, and extensive discussion on evidence in macaques can be found here (although I recommend reading the whole discussion and/or the study; the root comments are less informed than the leaf comments).
I believe there have been encouraging experimental results in other mammals, including primates, as well as human trials with surrogate endpoints. I also recall seeing a least one ongoing prospective cohort study with promising interim results. Will google and append links when I get a moment.
I would expect mild ketosis to compensate for hypoglycemia, but cognitive effects are of concern to me as well. Anecdotally, while practicing intermittent fasting regularly I did not appear to suffer any cognitive impairment.
I do feel (but yes, that's error-prone) that I've lower concentration/thinking ability when I'm late for a meal.
Also, my parents (both retired teachers, one at uni the other in secondary school) both noticed that pupils/students were less focused and more error-prone in the hour just before lunch, and AFAIK (but I've no link right now to point at) this was backed by more formal studies than just "personal experience".
There is also a certified increase of rate of car accidents in Muslim countries during the Ramadan month, due to lower attention/reflex speed when people are doing Ramadan, but AFAIK it's unsure how much is because of hypoglycemia and how much is because of dehydration.
Edit : for my own personal experience, it may also be because I'm on the skinny part of the spectrum, I weight ~55kg for 170cm, so I get hypoglycemia quite fast if I don't feed enough or regularly, it may very well be different for people who have more reserves than I do.
Being late for a meal is very different than restricting calories. If you eat a meal at the same time every day, your body gets in the habit of wanting to digest food at that point in the day. More blood re-routed to digestive system, less blood to the brain --> lower concentration/thinking ability before meal. Note I am partially pulling this out of my ass.
I feel better when coming back from lunch, so it's not the "re-routing blood to the digestive system". But it could be something with sugar level management, yes, my body expecting to be fed at 1pm, so not taking the expense to start using stocks to provide me with sugar when we are near that time, instead waiting for the coming meal, or something like that.
Anyway, I more wanted to say that diet/calories issues aren't simple, and that "rodents live 20% longer when on calorie restriction in a lab" is just weak evidence that it would be good for us to do so. There are many aspects to consider (differences between men and rodents, effects on intellectual abilities or overall well-being, immune system strength, capacity to recover in case of disease/wound, effects on different ages, sex or corpulence, ...) and studies that evaluate all of that are lacking.
Maybe calorie restriction is worth it, but there is just not enough evidence to tell. Saying "Most living people don't optimise for that either. If they did, more would practice calorie restriction." seems to me broad overconfidence.
Interestingly, the calorie restriction effect may just be because the mice used were overweight. article
Ironically, given the Western diet, even if that is 'all' CR is, it may still be a good idea and life-extending.
Discussed here; timtyler's aware of such results and believes the evidence still points towards CR (which is also my opinion).
In sensible CR experiments (which date back to the 1950s) the control mice are calorie restricted too, precisely in order to rule this possibility out.
What about the Okinawans?
What about them? They eat more and differently these days, and accordingly, Okinawa's life expectancy has fallen.
I was thinking about the pre-WWII Okinawans. Anyway, isn't what you mention further evidence that CR works, even below the not-morbidly-obese line?
It could be, yes. One question I have here is what is 'morbidly obese'? Is it like IQ, where it's essentially a relative ranking (the top fifth is the fattest and defined as morbidly obese), or do we have a clear bright line from biology where a certain weight is the crossing point between good and bad? If it is the former, then for all we know, Okinawans who were eating their fill were still above the bright line even though they look thin and fit from a contemporary American viewpoint.
Yes. My grandmother seems to not give a damn about how much longer she's going to live, only about how much Fun (which in her case essentially means food and cigarettes) she has every day before dying. And she has nearly explicitly admitted to that. (And no, I'm not just talking about the fact that she eats and smokes too much.)