The reason mice are used in labs isn’t because they’re a good model of humans, but because they’re easy to bread and have short lifespans.
Studies of caloric restriction in monkeys didn’t cause lifespan extension, casting doubt on its effect in humans.
Peter Attia (best source of longevity science) wrote about this 5 years ago.
https://peterattiamd.com/calorie-restriction-part-iia-monkey...
Humans (and other non-tropic animals like mice) have adaptation for seasonal food availability, and can go through extended fasting.
You just ignored the context of ketogenic metabolism being more similar in humans and mice than humans and chimpanzees.
~ George Box
Humans are part of the Primate order[0], as well as other great apes like gorillas, and chimpanzees too.
We (the Homo genus) did split from the Pan genus (chimpanzees & bonobos) 5 million years ago.
As of right now, it's as high as could possibly be. Please don't suppose comments stay wherever they were when you wrote your comment. It looks silly.
(Other than that, reasonable observations - thank you!)
Note that ketosis != fasting; ketosis == low carb, which can also be induced without fasting (but only by eating a low (near zero) carb diet). So are you sure you're not conflating 2 dimensions (how much we eat, vs what we eat)?
Funny enough, one of the reasons I respect Peter Attia, is that he's changed his mind several times, after new information came to light (i.e. he had an initial assumption based on weak evidence, then changed his opinion after he found stronger evidence). This is quite rare in general, an even rarer among the "influencers" (a.k.a. professional grifters).
The first time Peter Attia had to change his mind, is when his Nutrition Science Initiative (NuSI) collapsed. Long story short, his hypothesis was that carbs (or rather, the insulin response) make people obese, and that low carb diets drastically improve health. NuSi funded proper experiments to test this, i.e. they provided calorie-matched low-carb and non-low-carb diets. They failed to confirm the hypothesis.
https://www.wired.com/story/how-a-dollar40-million-nutrition...
NuSI funded two trials that could test the energy balance hypothesis. (This is an important point: these experiments tested the null hypothesis, which was energy balance, although the experimental tests were based on predictions made by the carb insulin model.) One trial, led by Kevin Hall and Eric Ravussin, was a non-randomized pilot study that they interpreted as consistent with the energy balance hypothesis. That interpretation was challenged by David Ludwig who led the other trial, an RCT that Ludwig interpreted as inconsistent with the energy balance, calorie-is-a-calorie model. Hall et al challenged that interpretation.
If Peter changed his mind, which his book suggests he did, it could not have been based on the results from the NuSI-funded trials because their interpretations were contradictory, as experiments in science often are. Peter cares deeply about scientific method so I'm sure he understands this.
Holistically: https://pmc.ncbi.nlm.nih.gov/articles/PMC5563491/#S1
More pointedly:
> Five healthy rhesus monkeys, three male and two female, weighing from 2.4 to 6.1 kilos, were fasted for periods of 2 to 4 days... With one exception, the monkeys developed a ketosis within 2 days
https://www.sciencedirect.com/science/article/pii/S002192581...
Note that Attia's article is about rhesus monkeys.
It’s not like we’re out here in the real world with a healthy and nutritionally balanced baseline. Most of us eat quite a bit of trash, so in the context of the real world the findings seem valid enough.
Shouldn't there be enough evidence to get an idea if there's possibly a correlation?
Medical science has clearly shown that this is bad for your kidneys. Possibly catastrophically bad.
Who should I believe, science or medieval superstitions?
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8377932/ > A total of 215 women were included in the study, 123 women fasted, and 92 women did not fast. Only 2.8% of women knew that fasting is forbidden in pregnancy. Sixty five percent of women reported weakness as the main reason for not fasting. The rate of gestational diabetes, pregnancy induced hypertension and preterm delivery was higher among women who fasted (17% vs 14%, 7% vs 2%, 9% vs 9%) respectively, compared to non-fasting women, but were not found statistically significant. There was no difference in anthropometric measurements of newborn, among both groups.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9931121/ > Fasting during pregnancy was associated with reduced birthweight, in particular for fasting during the first trimester (-352ˑ92g, 95% CI: -537ˑ38; -168ˑ46). Neither dietary composition nor altered sleep were directly associated with birthweight. However, dietary composition during Ramadan outside of fasting hours seems to moderate the fasting-birthweight association, which disappeared for women switching to high-fat diets.
As a Muslim, I can tell you we tend to over eat, generally after we break our fast. It kind of defeats the whole point of fasting. In most cases its unavoidable as breaking fast is a social event for most people.
Im guessing before food got abundant the results would be quite different, but again back then most of the world had little to eat any way.
The goals of fasting during Ramadan are not to train people for intermittent fasting. Its because the religion/god said so, and to some extent make you feel how the poor feel as thats how life works for them everyday.
There is also a thing about fasting every Monday and Thursday which pious people tend to do often. But in general I have seen only good things happen to people who eat less. Muslims or not.
> The investigators were comparing median survival between the CR and control (CON) groups, not longevity or lifespan per se.
As I read that, it wasn’t that the study showed that caloric restriction didn’t extent lifespan. It’s that they weren’t investigating the effect of caloric restriction on lifespan, so no conclusions can be made from the study.
TL;DR: there are 2 monkey studies, with unclear/conflicting results, both had pretty shitty diets, the calorie restrictions were severe, the benefits minimal at best.
According to Attia, the studies weren’t specifically studying life extension, and all the diets were non-typical for the monkeys being studied. So, to me, this argues not that caloric restriction doesn’t cause lifespan extension in monkeys, but that we cannot know from these studies whether caloric restriction with a healthy diet causes lifespan extension in monkeys, which is what we really want to know. I wouldn’t expect to extend lifespan by eating hamburgers and fries but less of them, and that seems analogous to what the studies did.
To me, this simply leaves the question of caloric restriction in humans unanswered instead of casting doubt on it. Big difference.
I don’t think there’s much meat on a mouse though, especially when the experiment is to have them eat less.
https://peterattiamd.com/ep-300-exercise-nutrition-fasting-m...
I see this too, for some reason people who don't fast kind of find it rude if people around them are fasting. Families even more so.
Studies on monkey's are not easy to repeat. Somebody should test caloric restrictions on mice with explicit goal of making it not work.
What does making some bad scientific study that tells you something incorrect about mice help?
I know I’m just nitpicking here but I believe you mean “inconclusive”. If we knew the findings specifically to be incorrect then we’d be learning something.
It's not about finding something inconclusive or incorrect. It's about finding all the ways you can make caloric restriction not cause extended lifespan in mice without harming them in some obvious ways that are hard to apply accidentally in research setting.
For example, maybe caloric restriction doesn't work if you feed mice badly inappropriate diet.
Chimps are also very muscular animals. Less fat to burn.