Carbonfiberboy 

I won't go into it, because it's laid out pretty well in this study and the title captures the meat of it, as it were::
https://newsroom.heart.org/news/8-ho...vascular-death

MinnMan

Oh, that's surprising. And sucks. Scanned briefly. Any hypotheses as to the systemic cause of the enhanced risk?

MoAlpha

This appears to be a meeting abstract, so not rigorously peer reviewed. For conferences, one just tends to weed out the obvious junk and it's unusual for anything to get rejected. It's a nice big study with a pretty long follow-up, though, so I'll give it the benefit of the doubt for now, while taking into account the caveats helpfully outlined in the press release. I'm sure we can think of other potential issues. At a minimum, however, intermittent fasting didn't prevent cardiovascular death in this group.

Then, "91%" sounds like a big increment, but it's relative to what I assume was a low base rate in the sample, so this probably isn't a major threat.

MoAlpha

One thought is packing all that eating into a short period and stressing the heart due to demand from the gut. It's not shoveling snow, but it's something.

PeteHski

Interesting. My first thought was that maybe those who were following an 8 hour time restricted eating plan might have been more likely to be doing so specifically to manage a serious health issue such as their weight. Otherwise why would a healthy person be inclined to follow such a restricted eating plan?

ZHVelo

Don't most humans do this when they do what is called sleep?

Iride01 

Possibly some of the people felt that 16 hours of no eating allowed them to binge on anything they wanted during the 8 hours. No matter how unhealthy that food is.

Sort of like when I started taking a statin, I felt like it was okay to put some of those things I missed back into my diet. IE. Butter on popcorn!


Or perhaps they were just confused and thought is was 8 hours of fasting then 16 of binging.

MoAlpha

Look at the amount of food-related concern and anxiety in this cohort of active, health-oriented, cyclists.

roadcrankr

Maybe I missed it, but a few matters did not become clear to me.
1. How did they select participants? (Random, volunteers, paid, sickly, etc.)
2. What type and how many of the study's individuals chose to fast? (All 20k participants or less than a hundred or some number in between.)
3. It said something about "...average age of 49..." I would think those within the study could reach their sixties, then, when people may become afflicted with heart ailments.
4. Those choosing to fast may do so because of other health issues, such as obesity, high blood pressure, diabetes, etc. Perhaps those underlying conditions become self-fulfilling.
5. Overall, the study seems to actively promote the idea that fasting automatically leads to death from cardiovascular disease.

Bogey Speedwell

Soooo, are the intermittent fasters, doing so to get back in shape? Which leads me to surmise the people fasting have a poorer cardiovascular track record.

Perhaps it’s like saying people using weight loss dugs are more likely to have heart issues.

john m flores 

I started skipping breakfast in the early 2000s because I got enough calories from American-sized lunch and dinner. But I didn't call it intermittent fasting; I called it skipping breakfast. And I don't do it religiously; if I'm hungry in the morning, I'll nibble or eat something.

But I guess I now have a 91% increased chance of dying of cardiovascular death. It's been nice knowing you all.

PeteHski

Yeah, I used to skip breakfast too so I could get an extra half hour of sleep before work. These days I just call it a lie-in and make it a couple of hours longer.

MinnMan

I believe there have been quite a few threads previously about intermittent fasting in T&N.

Intermittent fasting can be used for weight control.
There is also evidence (albeit imperfect) that it is of benefit for those seeking to control Type 2 diabetes or who are pre-diabetic.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9534344/

Generally, the practice is understudied, but previously, the medical community has considered it to be of possible benefit to many health risk factors.

From a 2020 review in the American Journal of Medicine:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7415631/

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PeteHski

Good point! But I bet not many here are on an 8 hour restricted eating plan unless they have some specific health issue driving it. The nearest I get is trying to cut out late night snacking, which for me results in a 12 hour eating window.

MinnMan

No, most don't if they eat 3 meals/day.

For example, I do intermittent fasting for several reasons. First, I try not eat after dinner (usually after 7 PM) to help control my acid reflux. , Second, unless I'm going out for a long morning ride or am traveling, I usually do not eat breakfast. This results in a 8 hours of allowed food consumption and a 16 hour fast, from 7 PM to 11 AM, generally 4-5 days/week. I find that this regimen helps me control my weight (largely because time rules help with self-control over snacking) and my blood sugar, which previously was on a trend towards type 2 diabetes, even though I exercised extensively (say, 7-9k miles/year on the bike) and was not overweight (5"10, 145-155#, depending).

MinnMan

Link to an older thread that I started about intermittent fasting, with some info that some here may or may not appreciate

Inadvertently started intermittent fasting

MinnMan

Also, a 2019 review in the New England Journal of Medicine may be of interest

Effects of Intermittent Fasting on Health, Aging, and Disease

https://www.nejm.org/doi/full/10.1056/nejmra1905136

Carbonfiberboy 

My WAG is that it's the fasting, not the eating. Folks who do intermittent fasting are probably already particular about their diet. OK, those of you who actually know something about this . . . Is it possible that gluconeogenesis works better with protein than fatty acids or might the enzymes associated with it have some negative effect? There's a study showing that among non-athletes, IF folks lost more muscle mass than fat mass. It's well-known that loss of muscle mass shortens life span.
https://jamanetwork.com/journals/jam...rticle/2771095

RH Clark

I've been eating all my calories in a 4–8-hour window for more than 5 years. It's not that big of a deal. I can eat from 11am to 7 pm if I want. The key is to do it at the same time frame all the time. It helps all kinds of body processes to have a break from having to digest food and release insulin.

I am very skeptical of the findings of the study even from the limited amount I reviewed it. For one thing the data was self-reported, so who knows how accurate it was. I would be interested to learn more details.

Andrew Huberman is a respected researcher, and teacher-scientist. In this video he discusses several peer reviewed studies concerning intermittent fasting. I find it to be better information than what is illuded to from the subject study.

MoAlpha

For those speculating that people with cardiovascular risk were over represented in the 8hr window group, the press release mentions that the effect was seen even among individuals with known cardiovascular disease.

Andrew Huberman is a neuroscientist turned internet influencer and hawker of supplements, who has done some interesting and important work on the visual system in rodents, among other things. He has no professional expertise in this area.

MinnMan

Presumably your first point means that they are controlling for that variable by comparing those with known cardio issues doing IF against those with who aren't, and those without known issues against same...

MoAlpha

Yup.

MinnMan

One study doesn't establish that IF increases risk for heart disease, and certaintly not for all cohorts. As already highlighted, there could be biases in the study that won't be understood until there are more studies. that's why well-studied connections between diet/lifestyle/environment and disease risk are subject to many studies with different experimental design, followed by metanalysis of those many studies together. And I have yet to see any well-framed hypothesis, in this thread or otherwise, of a causal mechanism.

But it's worth watching and worth further study.

Generally speaking, people are too quick to either fully accept or wholesale reject epidemiological studies that they do or don't like for whatever reason, not really understanding the key roles of replication and varying the designs of study in the step-wise improvement of our understanding.

Shorter: it's not all or nothing, folks.

MoAlpha

This one hasn’t even been published as a full paper yet, so it’s way too early to pass judgment on anything but the observational and self report methodology part. And don’t hold your breath for prospective, controlled, trials with comprehensive outcomes and multi-year follow-up, in this area. They are impossible to do.

PeteHski

This comment near the end caught my eye.

“it needs to be emphasized that categorization into the different windows of time-restricted eating was determined on the basis of just two days of dietary intake,”

I also wonder if many (or even any) of the participants actually followed the same consistent eating routine for the long haul. I know my eating patterns have changed several times over the last 20 years.

This just seems like an almost impossible study to control.