[hirundo]

> This study suggests that a vegan diet may negatively influence the outcome of surgical scars.

This is unusually damning to veganism-as-it-is-practiced if not to veganism itself. It would be interesting to see these results across a wide range of diets.

[asoneth]

I'm not sure any of the vegans I know would give up veganism in order to minimize their scars any more than the meat-eaters I know would give up meat based on studies that show it can be mildly unhealthy.

[_dax6]

Maybe I'm reading into it too much, but the outcome of this study seems to suggest there may be other healing-related issues attached to veganism.

[asoneth]

I wouldn't be surprised, though I would be similarly skeptical that other healing-related issues would sway people one way or the other either since (at least the vegans I know) don't adopt the lifestyle for health reasons.

Very large effects are unlikely given the number of long-term vegans who seem to maintain sufficient health. Whereas small effects might be considered a worthwhile sacrifice.

[spicymaki]

Agreed as a vegetarian, this study being called damning is a joke. Veganism has a pretty good track record with respect to health outcomes. Committed vegans that I know would still do it if it lowered their lifespan, because they are doing it for a higher cause (environmental, moral, spiritual, etc.)

[imwillofficial]

I reject your premise that eating meat makes you “mildly unhealthy”

[asoneth]

Exactly.

[To clarify: I am not qualified to judge the general healthiness of any particular diet -- any sufficiently popular diet seems to have conflicting studies showing it is "healthy" and others showing it is "unhealthy". The point I intended to make above was that most people either outright reject or remain unswayed by these kinds of studies.]

[badRNG]

> This is unusually damning to veganism-as-it-is-practiced if not to veganism itself.

I don't think a sample size of 21 is especially damning. Nor do I think that the study's authors would come to that conclusion either.

[tpoacher]

Depends. Emotive language aside (i.e. "damning") the low sample size is actually "more evidence" in the presence of a convincingly low p value.

It means that this particular sample of 21 people would have to be extremely atypical under the null hypothesis of no difference. Therefore, given its low sample size (and thus wide standard error), it is 'some' evidence that the effect size is also probably quite large.

[majormajor]

That doesn't sound right. The reason sample size is important is because the larger the group, the less likely the group is to be atypical. I don't think you can turn that around and then say "this group is small, which itself is evidence, because otherwise it would have to be extremely atypical to show a difference." That's completely circular.

The p-value is still the important thing because the p-value is itself affected by the sample size.

[stevenhuang]

No, effect size very much informs all of that.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3444174/

[tpoacher]

> the larger the group, the less likely the group is to be atypical.

Not true (unless I misunderstood what you were trying too say). The probability that a sample will be atypical under the null is exactly the significance level, and does not depend on its size.

What does change with size is that the distribution around the statistic gets more concentrated, meaning your threshold moves to the left, towards lower effect sizes.

Which also means that for smaller sample sizes, it is harder to reach significance, unless you're dealing with a fairly large effect size.

[colanderman]

"Veganism" denotes an ethical stance, despite the plant-based health foods movement co-opting the label, or some activists (ab)using health claims to promote a vegan diet. A study about scar tissue is in no way "damning" of it.

[centimeter]

One of several motte-and-bailey tactics used by vegans is going from

“Veganism is healthy”

To

“Veganism can be healthy if you exercise an impressive amount of restraint, discipline, and judgement in your vegan diet”

[petertodd]

_If_ you can get enough exercise, you can be healthy on pretty much any omnivore diet because it's so hard to not get enough nutrition, and extra calories don't matter if you burn them off. I personally lost lots of weight when I was cycling regularly to work and school (10km and 50km round trip respectively), as well as caving and climbing on weekends. Almost everything I ate was fast food, because I had hardly any spare time. But I was definitely healthy and felt great so long as I took enough days off (I was getting enough exercise that I simply couldn't do it every day).

Meanwhile, I know lots of people who have given up on vegan diets because they felt like their health was declining, even with regular exercise. I'm sure with enough care and nutritional science they could have gotten it to work. But it's so much easier to just add some animal products to your diet.

[jxramos]

I remember hearing the question asked someplace about whether any professional athletes are vegans, especially for the intense sports that require a lot of muscle rebuilding and maybe even contact sport healing and what not. That might illuminate things a bit.

[asoneth]

There is an advocacy* movie called The Game Changers which highlights several vegan athletes and makes the case that their plant-based diet contributes to their success. https://gamechangersmovie.com/

* I would not consider it a documentary as it has a clear agenda, but I found it interesting nonetheless.

[centimeter]

https://www.lonesomelands.com/new-blog/2019/9/16/t2amoscp1u1...

[jxramos]

that guy may be able to make a statistical argument with this sort of data. Number of injuries and percent of time on the bench with the two pools and a simple t-test or something.

[rektide]

Agreed that there are probably ways to remediate some of these effects.

I definitely favor smaller less impactful scarring, but also, so what? Calling ths "unusually damning" seems like a significant overinflation of concern.

For all we know, it may have far more significant pro-recovery characteristics associated with it. "Oh you built too much scar tissue? Your vegan diet also stitched your blood vessels back together really well."

[arkitaip]

dang really needs to get YC to develop an AI that can automatically add /s to ironic comment.

[stelonix]

I'd rather HN not allow such comments and we try to make debate here better than on the rest of the internet.

[centimeter]

Or people could work on their ability to identify normal human modes of speech.

[ben_w]

Given we’ve had the internet for over a generation with this issue being known that whole time, I don’t think that’s actually something we can do. Not in general, not from plain text.

[centimeter]

I think only morons, autistics, etc have a habitually hard time identifying sarcasm. These are not the people we should optimize the web experience for.

[ben_w]

Only when spoken, not when written: https://theconversation.com/why-is-sarcasm-so-difficult-to-d...

[yjftsjthsd-h]

Text inherently makes it difficult if not impossible to distinguish sarcasm that would be apparent with verbal/visual context clues.