dailycarbs wrote:BlueHeron wrote:Extreme calorie restriction will slow aging if you are a mouse. Results in monkeys are mixed. It seemed to slow aging when the controls were obese, but not when they were of normal weight, but results in at least one study were dependent on the ages of the monkeys when calorie restriction began (interestingly, results were not positive when monkeys were started on calorie restriction at a young age).
Here's a 23-year study of monkeys showing that health markers were improved, but longevity was not.
https://www.nia.nih.gov/newsroom/2012/0 ... t-survivalGenerally mouse studies give information that helps scientists decide whether to proceed with human studies. Sometimes results in mice are vastly different from results in humans. There is no evidence that severe calorie restriction in humans is any better than the McDougall diet. If you want to try it, knock yourself out, but the level of restriction that's required sounds pretty miserable to me.
2 out of the three longterm primate studies showed improved longevity and the one that didn't had some problems with methodology. CR consistently shows improvements in biomarkers that lead to health and longevity. We base many of our conclusions that our woe works on that same idea. It would be hypocritical to deny the same to CR.
As for level of restriction, benefits can be seen at below the 30% rate.
As to giving it a try, most of us here already are through the practice of calorie density.
CR is mainly an academic, truth seeking exercise for me. I am not promoting it or saying we should do it. Like most everything we know about nutrition and health, the studies continue and nothing can be deemed conclusive. We should be thankful for the work being done as many of the findings will help us to understanding health and longevity whether we calorie restrict or not.
My pet peeve is that I sometimes see a knee jerk reaction by people here regarding CR (not saying you). It reminds me of sad or paleo eaters when they are told of our woe. It's like their minds shut off because they assume, "potatoes and rice? That has to be wrong."
I would question whether people on this site are really following the CR restrictions. I went to a lecture by one of the CR researchers who works with mice, and he said maintaining the equivalent weight in humans would result in people who are alarmingly thin - like way below what's considered a healthy BMI. He specified a height and weight for men, but, unfortunately, I can't remember what it was.
By methodological problems in the primate studies, are you referring to the study that used leaner primates as the control group? I have seen that cited as a methodological problem, and I don't understand that. In fact, I think it would be better to compare the CR subjects to those who maintain a generally healthy diet and leaner weight to see whether it really has an advantage. (But maybe there are other methodological problems I haven't seen mentioned). When you compare any diet to the monkey equivalent of SAD (as at least one of the other studies does), it's not surprising that the group with the restricted diet would be healthier.
But of course, it's a very complicated field of research, which neither of us is going to do justice to with the time, space, and knowledge we have here (unless you're actually a researcher, and I don't know it - I'm just a lowly medical editor who has taken a few workshops in medical statistics). And if exploring it even just academically is interesting and fulfilling for you, then you should. It is certainly interesting.
I know what you mean about knee-jerk reactions. My own pet peeve is people who search high and low for so-called methodological problems and conflicts of interest when they don't like results, but ignore both when studies fulfill their preconceived beliefs (also, not saying you).