Why does meat make vegetarians vomit?
May 1, 2008 2:43 PM   Subscribe

Why do vegetarians vomit if they eat meat?

Every time I've seen a vegetarian eat meat, by accident or because they were giving up vegetarianism, they always vomited. I was just curious as to why this is. Does anyone know?

If you're going to answer, please have some knowledge about the subject and preferably have a source. I can come up with guesses myself.
posted by giggleknickers to Food & Drink (31 answers total) 2 users marked this as a favorite
posted by Perplexity at 2:50 PM on May 1, 2008

(I am not a vegetarian, but some of my friends are)

Mostly, they're just not used to the taste & mouthfeel of it, although some of them claim to be unable to digest it as well, which is extremely unlikely.
posted by Oktober at 2:50 PM on May 1, 2008

One data point - they don't always. The day he decided to give up vegetarianism (after 20 years), my husband ate steak in a steakhouse. No vomiting resulted.
posted by Daily Alice at 2:51 PM on May 1, 2008

I was a vegetarian for about three years, and I never vomited the times I ate meat accidentally (most famously when I bit into a scotch egg without having the faintest idea of what it was). I didn't vomit when I had my first cheeseburger after going back to being an omnivore, either; in fact, it was so tasty that I immediately ordered a second one.
posted by scody at 2:54 PM on May 1, 2008

Another data point: meat was accidentally consumed by a vegetarian in my house recently (the burger place frakked up and gave us two meat burgers instead of a meat burger and a veggie burger). There was no vomiting. I did get to eat both burgers, though.
posted by rtha at 2:54 PM on May 1, 2008

Ah, looks like it's been answered. I did look for it, but didn't find it. Sorry about that.
posted by giggleknickers at 2:56 PM on May 1, 2008

Veg-head for almost 20 years now. Firstly to clarify I'm not a veggie because of some abstract moral reason, I just find it to be a better diet. However, after about a year or so of my chosen diet I was jonesing for some protein so bad I ate a hamburger and it lasted about 40 min in my stomach. Now I can't even conceive of eating red meat - bbq makes me naseous when I smell it.

I think its as much a physiological as psychological response. If you cut meat out of your diet your body just adapts and so changes in that diet affect you adversely while you adjust. But the psychological changes are just as pronounced. You learn to loathe meat, just because you dont consume it anymore. It's not rational, its just true. I'm not even a real vegetarian because I eat fish occasionally but I would quite honestly hurl if someone placed a steak or a plate of ribs in front of me. Maybe its just a psychological process of training oneself to give up something that we are quite honestly designed to consume. I dunno, but the reaction is real. Perhaps a physician can comment and clarify.
posted by elendil71 at 3:08 PM on May 1, 2008

We don't (or at least, I don't), but my guess is it's as much a placebo response as anything. Munching away at some good bean curd roll or something and suddenly you're biting into a well-hidden and entirely revolting, slimy cube of pigdeath, and if you're a vegetarian or vegan for ethical reasons, all that horrible shit flashes before your eyes and I would totally understand it if somebody vomited and told me the reason they vomited is because they felt they had just participated in a murder.
posted by turgid dahlia at 3:11 PM on May 1, 2008

FWIW, I believe I'm one of the more fortunate ones who haven't had trouble with the occasional accidental meat taster despite having been vegetarian for 17 years. I once ate an entire beef burger once thinking it was one of those fake beef patties, but was disabused of it later when I went back to the shop asking what was in that burger. It might not have been strictly beef but it was real meat. :( No vomiting or otherwise adverse effects, though.

I'm a lacto-ovo vegetarian - unsure if the dairy products help the stomach handle the meat?

some of them claim to be unable to digest it as well, which is extremely unlikely\

I'd speculate that that is more of a psychological manifestation of reluctance to change their diet rather than an actual physiological inability to digest meat. Isn't the ability to digest meat built into the human body?
posted by WalterMitty at 3:13 PM on May 1, 2008

They don't.
posted by OmieWise at 3:13 PM on May 1, 2008 [1 favorite]

What OmieWise said. I know it's only anecdotal, but I have a really sensitive stomach and eating meat after 6 years of vegetarianism didn't even make me feel ill.
posted by amro at 3:25 PM on May 1, 2008

Notice that based on that previous thread (as well as this one), this doesn't seem to be a universal reaction. Also, since people sometimes say "vegetarian" to refer to vegans, it's unclear if the reaction is more common in vegans than in, say, lacto-ovo vegetarians.
posted by Jaltcoh at 3:39 PM on May 1, 2008

Current vegetarian here. I've not eaten meat in the past 8 years, but I know I somehow can't always take greasy stuff the way I used to when I was still carnivorous (and I used to eat lots of meat). Grease does not rest quietly any more. And meat - even the stuff referred to as "low-fat" - is very, very fatty compared to most of stuff I eat now. I also now find the stuff revolting at times. So there could be a possible reaction to the grease, but it's also probably at least as much a psychological reaction to eating something disgusting. And after all, there's really no physiological reason people would puke if they ate cat shit. Hell, dogs love it.
posted by dilettante at 3:50 PM on May 1, 2008

Yeah I was a vegetarian and then vegan for years. I ate a giant hamburger as my first meat meal in years and didn't feel the slightest bit out of normal.
posted by Science! at 4:03 PM on May 1, 2008

I've been veg for 18 years. I know many, many vegetarians who've been veg for as long or longer. Every one that I know that's gone back to eating meat has never had a problem. Personally, I think it's psychosomatic, a myth, or a fluke.
posted by dobbs at 5:10 PM on May 1, 2008

I'm a life-long vegetarian, and here's my anecdotal data:

There are a couple of occasions when I've accidentally eaten meat bits, including once when a pal snuck hamburger into the last bit of my pb&j at a McDonald (after which I vomited from McD's balcony) where I've become either front or back ill after meat. I can rule out the psychosomatics because I'd not known there was meat in what I was eating until I was sick.

There have also been a couple of times when I've eaten meat accidentally with no ill effects, though usually I can feel it in my gut and it's uncomfortable.

So I'm going to vote for there being a more precise trigger (type of meat? quantity?) than just "meat," at least when it comes to me.
posted by klangklangston at 5:11 PM on May 1, 2008

Ummm yea, a lot of people are TOTALLY wrong about it. I always heard "I'm a vegetarian, if I have meat, I'll throw up because my body doesn't have the enzymes to digest meat".

When I heard that, I knew it was wrong. It took me a long time to find out the answer though, since even biologists at my school were all about that answer.

Yeah, the answer is: If you're a vegetarian, you may or may NOT throw up if you eat meat. BUT it has NOTHING to do with not having the "enzymes" to digest meat. Two major enzymes break down meats in your stomach:trypsin and pepsin. Trypsin and pepsin also are responsible for breaking down non-animal based proteins. YOU STILL HAVE THEM IF YOU ARE A VEGETARIAN.

So...yeah. As to why some people vomit...I don't know! I agree that there may be psychological reasons behind this. I know of a few vegetarians that have broken their veg-days by feasting on a huge steak or burger...and no vomiting.

I'm also seen some vegetarians vomit after eating stew they thought was meat-based. And then they found out it wasn't.

I have a lot of experience with this because this was a huge part of my college experience. So I had to kinda know what I was talking about when I sat down with whoever to eat.

Good luck!
posted by hal_c_on at 5:13 PM on May 1, 2008

klangklangston...your friends or eating companions are MEAN. And just to put my 2 cents in, if I was eating a PB&J sandwich and found out I bits of McD's burger had been put in it...I'd vomit. I'm feeling faint just thinking about that. NASTY.

Although, I bet you did make some longtime McD supporters think twice about their dining preferences. GOOD JOB!
posted by hal_c_on at 5:17 PM on May 1, 2008

Well, actually, I was about 12, and had just popped the whole quarter-or-so of the sandwich that was left when I got back from the bathroom into my mouth and swallowed it, then had about three minutes of feeling weird until it came right back up and over the balcony into the main ordering area. It was the first time I had ever had meat, and obviously it didn't take, but I was pretty mortified and some manager came and told me that I had to leave. So it wasn't nearly a blow for militant vegetarianism; more the embarrassing barf of some kid who was only glad that no one he went to school with was there.
posted by klangklangston at 5:38 PM on May 1, 2008

They vomit because some people have conditioned themselves to be sick at the thought of eating meat.

I know someone who will instantly vomit if she even thinks she's eaten a pea.
posted by gjc at 7:34 PM on May 1, 2008

Yeah, 20 years veg here; probably once a year or so I eat a small serving of meat for one reason or another and I've never had any digestive trouble of any kind.
posted by LobsterMitten at 8:40 PM on May 1, 2008

I've always figured it's animal fats doing their thing. I have gone through periods where, while not vegetarian, I eat very little fat and not much meat. When I finally do eat something a bit greasy, it leaves me feeling nauseous and gives me the runs on an epic scale.
posted by tomble at 8:59 PM on May 1, 2008

I'll add to the chorus: vegetarian for 25 years. When I quit eating meat I felt no different (i.e. I didn't become pale, anemic, and disoriented, staggering about and running into things, as pro-meat propagandists want you to believe). During the past 1/4 century I have eaten meat a few times, never felt the slightest bit sick or different in any way.
posted by crazylegs at 2:31 AM on May 2, 2008

Meh. I can eat anything. I love vegan food, I usually cook vegetarian / pesctarian meals, but if I'm in a foodie situation with a carnivore (as I was recently), I will try anything. No vomiting.

It's all in their heads, dude.

I *do* make it a point to only eat meat if I know where it came from (I know farmers and live in a good area for local food). I just don't trust third world meat.
posted by chuckdarwin at 3:02 AM on May 2, 2008

I know several meat eaters who get sick from eating meat... there's your clue right there.
posted by ewkpates at 3:46 AM on May 2, 2008

It's all in their heads, dude.


No matter how many times that's repeated, it simply DOES NOT align with the evidence—that vegetarians get sick without knowing that there's meat in what they're eating.

So can we knock off the retarded "It's all psychosomatic" nonsense?
posted by klangklangston at 8:23 AM on May 2, 2008

Please forgive the thread hijack, but can someone please explain to me why a longtime vegetarian decides to stop being a vegetarian? Several comments here have mentioned it and I'm really curious. No judgement intended, honestly. I was just wondering.
posted by LuckySeven~ at 9:06 AM on May 2, 2008

These are interesting answers. I have a couple of data points to add. We have 3 vegetarian experiences in our house, and 3 different reactions to meat.

Mr. headnsouth is a vegetarian for religious reasons --- every once in a while he'll order pot roast or salmon or whatever at a restaurant, with no ill effect whatsoever.

Headnsouth junior2 was vegetarian from age 6 to age 11 for love-of-animals reasons --- extended family members tried on several occasions to trick him into eating "veggie burgers" & other things that were real meat & the one time the trick worked, he got really angry but he didn't get sick. He's back on selective meats now with no ill effect.

I'm veg too, and came to it over time as, animal by animal, I got grossed out by the dead-flesh-ness of meat. Not religious, not pro-animal, not really moral at all. For me it's been physiological from the beginning. I do not have a sophisticated palate but somehow I know when dead animal parts are mixed into my food, whether in broths/sauces or via the processing (like gelatin or something). I grew up on Maryland blue crabs and I would love to sit for hours with a bushel of crabs, cold beer, & good friends ... but I can't =( And it's a big hassle sometimes when I just want a simple tuna sandwich, or a burger on the run. But it really does turn my stomach and I definitely would puke if I accidentally ate part of a dead animal.

And just to round things out, headnsouth junior1 has been an omnivore all along, but prefers tofurky to the real thing & has a visceral reaction to mushrooms (which are a main source of umami for vegetarians).
posted by headnsouth at 9:07 AM on May 2, 2008

After nearly 20 years as an ovo-lacto vegetarian I get sick from eating meat, including at times when I didn't know that I'd eaten it until after I recovered from the sick feeling. I have no idea why it happens. It's not usually violent vomiting, but it's pretty unpleasant cramps and other gastrointestinal symptoms. But in any case, I think that people like me are counterexamples to the "it's all in their heads" theory. I'm not saying that it's not psychosomatic for some people some of the time. I'm just saying that for some of us some of the time, it's a genuine physical reaction.
posted by decathecting at 10:24 AM on May 2, 2008

Former vegetarian of many years. Never got remotely sick when I went back to meat. Maybe it was those 16 years of eating meat before I went veg.
-Some people have a legitimate physical reason as mentioned in the previous thread. Especially people who stopped eating meat as kids or never ate it in their lives.
-Some of them have convinced themselves that they can't eat meat and their need to vomit psychosomatic.
-Some of them make themselves vomit or lie about it to prove a point.
Seriously. I've known people that have done this. Most of them admitted it later once called out on it.
posted by fructose at 5:23 PM on May 2, 2008

"No matter how many times that's repeated, it simply DOES NOT align with the evidence—that vegetarians get sick without knowing that there's meat in what they're eating."

Absent some evidence that there's actually a physiological mechanism by which someone could become de-adapated at eating meat, I think you should consider the possibility that your evidence is an example of selection bias. How often have you gotten nauseated or sick when you didn't eat meat? On an occasion when you discover that you unknowingly ate meat, you'll naturally assume that's the cause. And eating something one finds abhorrent is extremely memorably; it's easy for you to discount all the times you've been nauseated when you didn't eat meat.

I'm sort of an anti-vegetarian. Not philosophically, mind you, but from preference since early childhood. And numerous vegetables nauseate me. I find that just the suspicion that I've eaten some vegetable that I dislike will nauseate me. It's entirely psychosomatic and an oversensitivity. But that doesn't make the nausea or disgust any less real.
posted by Dances with Werewolves at 3:57 AM on May 4, 2008 [1 favorite]

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