Polaris OBark

I've personally learned quite a lot from arguing with MoAlfa. We are fortunate to have his contributions and insights.

PeteHski

The study itself (or preview) already covers the potential flaws and limitations of this kind of long term study with limited data. The authors are not claiming that it is a causal link and one of the lead authors does express surprise at the data findings, given previous findings from short term studies. But what can they do? Just ignore the data? Or try to discover why there is a surprising link?

RH Clark

In that case why wouldn't you give more credit to multiple peer reviewed studies indicating benefits of IM fasting?

RH Clark

I don't think there is a link other than it was the one question asked? If the authors purpose was to find out if there was a link between IM fasting and heart disease, why wouldn't they try to rule out any other "known" contributing factors from the study group? My personal opinion is that the study was intentionally biased.

MinnMan

It is true that caloric restriction and IF are sometimes conflated, particularly in animal model studies, and that this may not apply to human behavior.

But please back up your statement with citations to the peer-reviewed evidence.

Polaris OBark

Before hearing about this, I thought those benefits were well-established. But if new evidence emerges to the contrary, I will have to alter my opinion. If it turns out it that the newly reported analysis is a mistake, or a red herring, or bad statistic or whatever, then I will default back to the original position that IM is purely beneficial.

I've never tried IM fasting, but I have pretty much assumed the benefits greatly outweighed any potential risk. This newly reported preliminary finding is something I currently regard more as a heads-up. If it stands up to peer-review and its findings can be replicated, I'll regard it as a refutation of the assumption that IM is purely beneficial.

I don't have any personal stake in this. If IM is a way of reversing typeII diabetes and lowers cardiac risk as a consequence, I think it should be more widely promoted. I would really like for that to be the case, but if evidence to the contrary emerges, we can't just ignore it because it is "bad news."

Looping back to the quoted question, the answer is that (scientific) knowledge progresses, and sometimes that involves abandoning previous assumptions. The same logic applies to the following trivial example: I have a hypothesis that all swans are white. I observe 49 white swans, and conclude my hypothesis is correct. But I walk a mile upstream, and encounter one black swan. That is 49 observations of white swans vs. one observation of a black swan. Can I still conclude that all swans are white?

hubcyclist

https://pubmed.ncbi.nlm.nih.gov/29419624/

zandoval 

What ever the case, intermittent fasting or not, have a plan. And and remember if you are hitting the wall...

MinnMan

Interesting, but this study is limnited to the topic of weight loss, which is hardly the only potential benefit of IF - for example, for treatment or limitation of high blood sugar. (or the many other benefits noted in peer reviewed papers posted above)

your statement was Perhaps I misunderstook that for a more general statement, when you were thinking only of weight loss?

MinnMan

Interesting, but this study is limnited to the topic of weight loss, which is hardly the only potential benefit of IF - for example, for treatment or limitation of high blood sugar. (or the many other benefits noted in peer reviewed papers posted above)

your statement was Perhaps I misunderstook* that for a more general statement, when you were thinking only of weight loss?

*deliberate

RH Clark

If this study had illustrated any correlation between IM fasting and heart disease, I would be extremely interested in the findings. As it stands however with no exclusion of multiple factors that are proven to cause or at least increase risk of heart disease, and no verification of the accuracy of the information used, I see this study as less than worthless. I say less than worthless because it may influence people from adopting something proven through multiple peer reviewed studies to be extremely beneficial. You have to ask why this particular clearly useless and completely unscientific study has received so much publicity.

work4bike

Studies on human health and nutrition will continue to be only useful for headlines, period.

My recommendation: Use prisoners to do real science experiments

RChung

Yikes.

NHANES (and its predecessors) has been around for decades. It's the basic national survey that tracks nutrition and health, much like the Census tracks population growth and distribution, vital statistics track fertility and mortality, employment surveys track unemployment rates, and price surveys track CPI and other economic variables. It's pretty well-established, and NHANES (and the linked mortality dataset) have been extensively reviewed and have generated innumerable discoveries over the years. That you think NHANES is a one-off study shows you don't know what you're talking about.

That said, NHANES (and the linked mortality dataset) aren't used to "prove" hypotheses -- they're used as an early warning system, and to generate hypotheses. The reason why this poster presentation is getting so much attention is *exactly because* the finding is so counter-intuitive: the links between calorie restriction and weight loss is solid, and the link between excessive weight and mortality is solid. The expectation then is that the link between IF and mortality would be solid. The reason that particular link is so hard to research is for two reasons: first, you need a long time to examine mortality as an outcome, and, second, the linked mortality dataset hasn't been around that long. That means that there are lots of findings that couldn't have been done before the last few years. It also means that others will start to look into this question and perhaps figure out specific research studies.

So I'm sure the question of a link between IF and mortality will eventually get resolved, though not soon. The question of why you're so invested in this probably won't get resolved, but I'm much less concerned with that.

MinnMan

I write the following having already made clear that I think the published study* is of limited use. Also, I continue to follow an IF diet.

*Edit: actually, not published at this time. rather, a poster presentation

When I compare your discussion of the study, as compared to RChung and MoAlpha's discussion, I see a very large disparity in factual characterization and in understanding of the experimental design.
Further, your text displays a clear agenda. You are coming in too hot with criticism, resorting to strawmen arguments not actually based on information in the study.
IMHO, a dispassionate audience would be advised to read MoAlpha and RChung's discussion for a better understanding.

terrymorse 

Regarding intermittent fasting (IF) versus general calorie restriction (CR) for longevity, this study with mice found that restricting eating to the daily "active period" was about twice as effective as eating the same calories around the clock.

Findings:

• CR increased lifespan by 10%
• IF increased lifespan by 20%
• IF subjects had higher insulin sensitivity and blood sugar stability
• IF got deadly diseases at far more advanced ages

-- Acosta-Rodriguez et al, Circadian alignment of early onset caloric restriction promotes longevity in male C57BL/6J mice, Science 2022

Mice aren't humans, but 20% vs. 10% is quite a difference.

genejockey 

No, it's shoveling food!

Polaris OBark

I've peer-reviewed probably several hundred papers and grant proposals over the course of my career. I don't consider myself qualified to judge the merits of this study, especially based only upon media or other third-party reports. I am not sure how you are able to do that, either.

By the way, which of the multiple peer-reviewed studies explicitly examined the incidence of heart disease in IM fasting? It is possible for IM fasting to have many benefits, but also some previously unrecognized harmful effects.

MoAlpha

genejockey 

The "Take Home Lesson" seems to be that there is not compelling evidence that one should not either adopt or not adopt intermittent fasting with any expectation of increased longevity beyond simple caloric restriction.

terrymorse 

A few things from this study poster are concerning. For the < 8-hour restricted eating group, which had the higher risk of CVD death:

• they had the highest BMI of all groups (29.9 vs 28.5 reference group)
• they self-reported a higher rate of CVD to begin with (8.6% vs 7.7% for reference group)
• they self-reported the highest rate of smoking (27.1% vs 16.9% reference group)
• they had the largest percentage of Black participants (23.2% vs 6.6% reference group)
• they were the smallest group in the study (414 out of 20,078), with just 31 CVD deaths

These are all reasons to be skeptical of this reported higher risk of CVD death from intermittent fasting.

RChung

Your concerns (about BMI, CVD, smoking, and race) were their concerns, which is why the risk model adjusted for "age, sex, race, total energy intake, education, income, food security status, smoking, drinking status, leisure time physical activity, diet quality score, BMI, BMI squared, and self-reported health condition status." In addition, the analysis looked at separate CVD status. But you're absolutely right that the most time-restricted group was the smallest.

Carbonfiberboy 

I was just checking out the poster summary of the study. My OP is dated 3/19. The PowerPoint poster is dated the same, but I don't think that poster was up when I posted, so some of this is new to me, like the ages of the study groups. The group with youngest mean age, the IF group, had by far the highest death rate. IMO 31 out of 414 is not a small number, "just", and over a median timespan of 8 years, though the longest time period was 17 years, meaning that some participants might have been as old as 60 at study end. A possible correlation might be income/work. It's possible that some low income groups might wind up doing IF involuntarily and might have a typical low income diet, hence the high BMI.

noglider 

Here is a link to the NY Times article accessible from outside the paywall.

noglider 

Gabe Mirkin wrote this article where he thinks the results of these studies are suspect.