Basically, rhesus monkeys on a restricted calorie diet only lived longer if you remove "non-aging related deaths".
But some of those deaths (eg, dying under anesthesia during a blood test) could have links to their diet, so removing them is just withdrawing non-supporting evidence to prove your (pharma-funded) hypothesis.
In other news, riding your bike to work is considered safer than driving a car ... once we remove those cases of bike-riders killed in car collisions.
Replace that with could have been caused by aliens to see how ridiculous that sort of claim is. There is no reason to suppose that dying under anesthesia is related to the diet.
Also your analogy doesn't make any sense. Perhaps if they removed bikers that died in traffic accidents while not riding a bike. And then you could argue 'bikers behave differently in traffic, so perhaps biking was the cause'... yeah, and perhaps we should also take the phase of the moon into account, just to be sure...
I haven't read the studies. Still, why isn't it reasonable to think that a monkey that eats too little will die more readily under stress? You can remove clearly unrelated causes (e.g. monkeys run over by bicyclists), but it's not nearly so clear for anesthesia.
Define 'stress', especially for these animals. Wouldn't you think that living in a laboratory cage is 'stressful'? If that's the daily baseline, I can't see how 'stress' can be a catchall explanation for even borderline cases. Administering anesthesia is a form of surgery. Even if they're related, would you want to say that death during surgery is a form of aging?
More importantly, deaths are just one of the variables being measured. The diet seems to improve quality of life, not just raw quantity. That's reason enough to be interested in these findings.
Furthermore, the author of this blog seems to doubt the role of Science in publishing these findings. The money they make has no bearing on the results. Other scientists, doing closely related work, reviewed the work in excruciating detail (read the footnotes, not the press releases) and found its clear scientific value. Sure, blame the media for the headlines. But the work, as a status report on the field, is very encouraging.
Because the monkeys weren't being underfed and it's a straw man to suggest they were. Tibetan monks get by on much less food than we do and they will still kick our asses anytime.
You're assuming that a monkey that eats 20% less than a monkey that's given the choice to eat as much as it wants necessarily isn't underfed? Maybe. But without some other research that I've missed, that really begs the question.
I think anyone living in a western country has enough data to realize that people eating a western diet tend to be overfed, so the comparison between westerners and Tibetan monks has little to do with monkeys.
In the caloric restriction experiments, the nutritional density of the food the animals are fed is almost always increased. Fewer calories, same levels of protein, nutrients, etc. It's not just a matter of 'less'.
From what I've read, humans on caloric restriction diets have to design their diets carefully, to increase the nutritional density of their own food supply. (E.g. http://www.calorierestriction.org/Getting_started)
Do you really think your casual pondering of the matter has revealed an insight not obvious to the experienced, professional scientists who designed and are now running this large scale, multi-decade experiment?
It beggars belief they have not considered, and painstakingly controlled for, such factors.
> There is no reason to suppose that dying under anesthesia is related to the diet.
If monkeys in one group were more likely to die under anesthesia than monkeys in a different group, I'd suspect that something is going on. (Being unimaginative, I'd exclude the possibility that dying under anesthesia causes a low calorie diet.)
If two monkeys in one group died under anesthesia, that doesn't constitute ground to conclude they were more likely to die: it is simply not statistically significant. Hence you may subtract them from the age related deaths.
> If two monkeys in one group died under anesthesia, that doesn't constitute ground to conclude they were more likely to die
I didn't say that two monkeys constituted statistical significance.
> Hence you may subtract them from the age related deaths.
You can subtract them because they're not statistically significant, but you can't conclude that there isn't something going on, which is what "there's no reason to suppose" means.
Suppose that odds of death due to anesthesia is really low (which it is) but that calorie restriction increased it by 10x (which we don't know either way). 10x a really small number is small enough that this study can't observe the effect because it doesn't kill enough monkeys. And yet, that 10x can easily cause two deaths in one pool while the other has 0.
I think his point would be best supported by the note that the study has not found a statistically significant difference in mortality between the restricted and unrestricted diets. It found that aging-related causes of death (cancer and heart disease) were reduced by a factor of three. This implies that the calorie restricted monkeys had higher-than-control rates of mortality due to non-aging effects, such as anesthesia and disease.
But some of those deaths (eg, dying under anesthesia during a blood test) could have links to their diet, so removing them is just withdrawing non-supporting evidence to prove your (pharma-funded) hypothesis.
In other news, riding your bike to work is considered safer than driving a car ... once we remove those cases of bike-riders killed in car collisions.