Intermittent fasting linked to a 91% higher risk of cardiovascular death | Hacker News Reader

Intermittent fasting linked to a 91% higher risk of cardiovascular death

eurekalert.org

88 pointsgeox57 comments

Its a retrospective analysis that didn't even adjust for weight! "Factors that may also play a role in health, outside of daily duration of eating and cause of death, were not included in the analysis"

"It will also be critical to see a comparison of demographics and baseline characteristics across the groups that were classified into the different time-restricted eating windows – for example, was the group with the shortest time-restricted eating window unique compared to people who followed other eating schedules, in terms of weight..."

Im worried that this seems to be done by the American Heart Association which i thought was pretty reputable. Maybe the study is being reported on out of context or something.

It would seem that most people on the diet are prescribed it by a medical doctor for out of control weight problems.

By the same token one could claim that any kind of diet is associated with an increased risk of death, but in reality this would be because overweight/obese people are the group most likely to seek out dietary interventions.

The wording of the questions also matter a lot but are near impossible to find. In this case, no one can read the actual paper since it is embargoed at this time.

This isn't how science is supposed to work, imagine if Maxwell published just a headline and hid his formulas behind paywalls.

It's preliminary research presented at a conference, in the last 24 hours.

So what, this isn't the next iphone. Publish the details of the study.

So far this is marketing clickbait. It's about as far from the scientific method as you can get.

Have you watched the presentation? I expect you'll see details there. Also, there are details at the American Heart Association article (another HN post).

Presentations of preliminary research is standard.

> It's about as far from the scientific method as you can get.

It's hard to grasp how that is true. I think more outrage and exaggeration are not helpful to anyone at this point in history.

Why even do a study if you're going to do that? I've seen a few studies that just fail to account for really basic stuff.

Why?

I would suspect it is some type of clickbait "science".

The reason to do this study is to produce the headline and have us read it.

This certainly has nothing to do with how someone like Karl Popper would define science.

> American Heart Association which i thought was pretty reputable

The same association that says soybean oil and cheerios are good for you

It's just a poster being presented at a niche AHA sub-division meeting from some researchers in China trolling the US based NHANES data

It's presenting to present, just part of the game of academics, and it does not represent an opinion of the conference sponsor (AHA) at all

edit: here is the link to the abstract for anyone interested https://www.abstractsonline.com/pp8/#!/20343/presentation/37...

I can think of more than one cause for this unexpected result.

How about this:

Unhealthy fat people with big atheroma plaques enroll in study. The study gives them some motivation to improve their health (to look good on results). They start a diet => they get included in the "restricted diet" in the study, they also start exercising, atheroma plaque wall ruptures due to stress => heart attack => death.

> “It will also be critical to see a comparison of demographics and baseline characteristics across the groups that were classified into the different time-restricted eating windows – for example, was the group with the shortest time-restricted eating window unique compared to people who followed other eating schedules, in terms of weight, stress, traditional cardiometabolic risk factors or other factors associated with adverse cardiovascular outcomes? This additional information will help to better understand the potential independent contribution of the short time-restricted eating pattern reported in this interesting and provocative abstract.”

So correlation is likely just a data artifact of poor data analysis and nothing to do with intermittent fasting?

I was thinking a similar thing while reading the article, where people who are doing intermittent fasting are more likely to be overweight and less healthy than someone who isn't doing intermittent fasting. They saw an increase in people with existing heart disease as well, so perhaps more people have less healthy hearts in general than they realize?

Reminds me of an alternate explanation of the Benadryl/diphenhydramine / dementia link: the people using diphenhydramine as a sleep aid probably have sleep problems, and their sleep problems could be the cause of earlier dementia.

My gut reaction: Intermittent fasters who are not doing it entirely by choice are going to have other stress markers. And those are highly correlated with cardiac function.

Exactly, this has come up before in other flawed studies. [1]

"Participants" are not necessarily fasting in the sense that the sensationalised headline/paper is making out.

More, good quality, studies are needed.

[1] https://www.foundmyfitness.com/topics/fasting#fasting-concer...

This just in: people on diets are overweight!

that's a fairly myopic view of the word 'diet.' lots of different people are on lots of different diets for lots of different reasons, e.g. bodybuilders or those with allergies.

(swoosh)

if the comment i replied to posits that people on diets are overweight, and there are people on diets who aren't overweight—then why don't you go ahead and finish that logic for me.

not like any of this back-and-forth is whatsoever relevant to the thread anyway.

and btw, i think the insult you were looking for is spelled 'woosh' or 'whoosh.' onomatopoeia and all that. a 'swoosh' is what basketballs do.

No, that's a quote from someone they interviewed who hasn't read the full paper (the full paper is not yet available). They are saying that the details of the study will determine how significant the results are.

> So correlation is likely just a data artifact of poor data analysis and nothing to do with intermittent fasting?

You have no idea whether the data analysis is good or not; the only thing that was released is the abstract.

Isn't the proportion of people who are obese and therefore go on this diet also going to be much higher? They appear to not have controlled for anything.

So in essence the implied cause and effect here for most people reading this headline (intermittent fasting causes cardiovascular death) is actually backwards: (people who are unhealthy are more likely to initiate an IF diet).

Reminds me of the story around diet soda. Some initial association studies found that there was an association between diet soda and several negative health outcomes but upon further investigation the evidence seems to be that it does not cause them.

They appear to not have controlled for anything.

this is 99% of health/nutrition science in a nutshell . "People who drink soda more likely to die." But they also tend to be poorer.

This is such a recurring pattern that it's kind of amazing we even take these reports seriously any more. Studying nutrition is so extremely challenging that outlets ought to have a very high bar for study quality and reject ones that don't control for such obvious confounding variables.

edit: fixed sentence tense

For the benefit of readers, here's the quote from the article indicating no controls:

"Factors that may also play a role in health, outside of daily duration of eating and cause of death, were not included in the analysis."

Reminds me of Impossibly Hungry Judges [0]. When an effect is _too_ strong your first instinct should be to question it.

I seriously doubt that eating patterns could have an effect on heart attacks similar to smoking, but maybe I'm wrong.

[0] https://nautil.us/impossibly-hungry-judges-236688/

> “Although the study identified an association between an 8-hour eating window and cardiovascular death, this does not mean that time-restricted eating caused cardiovascular death.” ... Factors that may also play a role in health, outside of daily duration of eating and cause of death, were not included in the analysis.

Sounds like this was entirely confounded by people with health problems trying to eat healthier and means basically nothing.

Seems silly to not, at least, split the population into those who made a choice to fast and those who couldn't eat. What an incredibly low signal to noise ratio.

What causes people to pursue studies like this? Or stop so, objectively, early in the analysis? Money runs out?

Very dubious. Unfortunately there isn't a paper, this is being presented at a conference, so it's difficult to critique it.

There was a similar study though published back in 2022: "Meal Skipping and Shorter Meal Intervals Are Associated with Increased Risk of All-Cause and Cardiovascular Disease Mortality among US Adults" [0].

The problem with that study is easily found in the results section:

> As shown in Table 1, compared with participants with three meals per day, participants eating fewer than three meals per day were more likely to be younger, men, non-Hispanic Black, with less education and lower family income, current smokers, heavy alcohol drinkers, higher physical activity levels, lower total energy intake and lower diet quality, food insecure, and higher frequency of snacks.

In other words, if you do an observational study you're going to get a lot of people of poor socioeconomic status with unhealthy habits (e.g. smoking) who skip meals. That's a very different population from an average person who starts intermittent fasting as an intervention. Consequently, the results are useless for showing the causal effect of intermittent fasting.

That is a different study to the one that's linked, but they both seem to share the exact same methodological shortcomings, so I think both can be equally as readily dismissed. For that matter, they're both studies of a cohort of ~20,000 US adults, so they might actually be using the same dataset.

[0]: https://www.jandonline.org/article/S2212-2672(22)00874-7/ful...

Reminds me of studies showing the early retirement results in earlier death, without accounting for people who had to retire early because of poor health.

Here's the abstract: https://www.abstractsonline.com/pp8/#!/20343/presentation/37...

This is a very surprising result, and it's hard to know how to interpret this with just the abstract and not a full paper. They used a survey where data collection started in 2003, well before intermittent fasting was all that popular. So my first question is what fraction of people fasting for 16+ hours per day were doing it intentionally vs. unintentionally. It's well known that loss of appetite is a poor prognostic factor for people with end-stage diseases. There's also the question of what proportion of people were involuntarily fasting due to lack of access to food. So if the study includes people who are unintentionally fasting, that's a major confounder.

Dr. Sacthin Panda[1] is a big proponent of time restricted eating, and was one of the people that has found the short term health benefits to time restricted eating. There's a famous firefighter study on the topic he led[2]. Something, I understand, that I thought also translated to long term benefits (at a minimum in animal models).

I will be curious how he reacts to this study

1 - https://twitter.com/SatchinPanda

2 - https://www.salk.edu/news-release/time-restricted-eating-imp...

>"So much is unclear about this study. In particular, why were the particular two days chosen to measure times of eating? How do they know whether food was eaten outside the 8-hour window and just not entered in the questionnaire?" David Spiegelhalter, emeritus professor of statistics at the University of Cambridge, said in a statement. "This abstract should not have been graced with a press release." [0]

[0] = https://www.businessinsider.com/intermittent-fasting-linked-...

I suspect this is related to a lot of people using IF to gorge on unhealthy foods. They openly brag about it on forums and social media.

Having high glucose, saturated fats, and insulin for 8hs can't be good for your body. People love magic solutions.

I suspect a similar effect will happen with Gen Z junk food vegans.

https://www.mayoclinic.org/diseases-conditions/heart-disease...

Self-reported data means that those on intermittent fasting are likely already more overweight than those not. Moreover, those that are overweight want to be on a diet so probably report being on a diet more than those who are not. Overweight people die earlier.

I’ve read your comment before the article, which means I’m left in the funny position of wondering how they get self-reported data from dead people. That would seem to be the real breakthrough! (It is a temporary bit of confusion entirely of my own making, which I’ll clear up shortly)

It looks like it’s self-reported data from the first year where there’s at least two days of logs. How could anyone extrapolate anything meaningful from two days of eating logs? So confusing.

I feel like I'm missing something or this is a flawed study. What about the actual diet? Do these people exercise regularly? Are they overweight/out of shape to begin with?

So they gathered gender, ethnicity, and diet information (self-reporting), but no mention of exercise, lifestyle, or if they have a genetic disease that might increase the risk of cardiovascular issues?

It's sad this got flagged within 45 minutes and 72 points.

I've done IF for many years but I don't like how it's like a cult. We need more studies.

Whatever diet you follow, you still should eat healthy and exercise.

@dang

Looks like a lot of people on HN do IF...

> I've done IF for many years but I don't like how it's like a cult.

The comments and flagging are consistent with that, at least.

91% higher risk, so, not quite double the baseline risk, which is not described. And there's no paper to review, because the study is being presented today - no doubt to greater effect thanks to it contemporaneously being in the "news."

> The study’s limitations included its reliance on self-reported dietary information, which may be affected by participant’s memory or recall and may not accurately assess typical eating patterns

Bad data highly likely here.

If this was true, humanity would have never survived.

self-reported data is a no from me, dawg

Why do they always headline the % change but not the actual %?

2x negligible could still be negligible...

Yeah, especially given we don't know what baseline is. Like, did 58 people die of a heart attack and 38 of them had intermittently fasted?

Without knowing what these numbers mean really hard to draw any conclusion. Also, somewhat irresponsible for eurekalert to publish something like this on an unreleased study.

True, but given that cardiovascular disease is one of the leading causes of death, I don't think that in this specific case it's negligible.

By far the bigger problem IMHO is not controlling by weight (at least, the article seems to hint that doing so might happpen in further research...), which is highly correlated both to cardiovascular disease and the chance of being on a restrictive diet plan. "Fat people more likely to have a heart attack, and also to be on a diet" doesn't have the same clickbaity ring to it.

let me think of one confounder… people on the diet may be overweight!

This is the most outrageously flawed and disingenuous study I've ever read and goes against the grain of every single other highly reputable study done in the last 20 years.

Agreed. It seems like a completely garbage analysis.

Probably why it's reported by a garbage website.

Relative or absolute?

> That which is put forward without evidence, can also be dismissed without requiring evidence.

Wake me when there's a study with a methodology. This is just a press release.

Are pharmaceutical companies starting to see a decline in sales? Recently, the process of autophagy was praised, and its discoverer even received a Nobel Prize. Starting today, I'm beginning fasting because if they want to convince me that it kills, I'm now certain that this is another lie.

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