Vegetarians are unable to digest meat...apparently?

I’ve recently encountered some people online who claim that individuals who subsists on a vegetarian diet lose the ability to digest meat (vomiting or suffering some other digestive complaint if they do), which is something I find quite strange for a number of reasons;

[li]Humans are omnivores, surely the ability to eat meat (or vegetation) is a result of the physical digestive system and not something that would change.[/li][li]In theory meat should be easier to digest than plant matter (as my understanding goes).[/li][li]My mother is a vegetarian and on the occasions she’s eaten meat by accident there haven’t been any problems.[/li][/ul]

Anyway, can anyone confirm or deny this claim. If they’re wrong I’d like to correct them, if they’re right I’d like to know how my mother’s dietary habits fit into all of this.

I’m not up to GQ spec on this, but…

I think any sudden changes in one’s diet can be problematic. Meat requires different digestive processes than vegetables. I don’t think vego’s lose the ability to eat meat forever, but if they get a sudden hankering for steak, they’d need to wean themselves back onto it slowly, so that their gut can get used to the idea.

Pretty straightforward. If you haven’t eaten meat for quite a while, the taste, texture, grease, psychological impact, etc can make some people hurl.

Digesting meat if you haven’t had any for a long time can lead to “radioactive” gas, constipation and/or the hershey squirts. Again, you’re digesting something that your body is not used to, and contains animal fat.

It’s not that you lose the ability to digest certain things, but your body is not used to doing so. Think of it as the natives in one locale can drink the water, and you visit and get the trots. It’s just “water” right?

Not sure the science behind this, but I was a vegetarian for 10 years. Pretty hardcore for a few years of that, less hardcore, then the last 5 years of it had some seafood. YMMV, but I had not had any meat for about a year. Got out of my first 3 month trip to China and straight to a McD’s and a Big Mac. It was great or at least the first half was great. Sucker came back up about 30 minutes later. I had a few other experiences, including one where someone snuck in some meat. Not sure if it was psychological or physiological or both, but couldn’t keep it down.

I was a vegetarian for over 20 years. One day I decided to stop that and start eating meat. I didn’t suffer any ill-effects at all, nothing whatsoever. My digestive system didn’t appear to be even remotely bothered at the sudden change in diet. So, no, there’s not much truth to the myth that veggies aren’t able to digest meat. At least, not in my deeply personal experience!

Your gut is home to 500 or more different species of bacteria, which aid your digestion in various ways. When you make long-term significant changes to your diet, you adjust the ecology, favouring some species and inhibiting others, but with an overall effect that the populations in there are those best able to work with what you’re eating.

When you change again, it’s bound to take a while for the balance to change again - in the meantime, the overall process of digestion is likely to be suboptimal.

Some anecdotal personal experiences:

I’ve been a vegetarian for 13 years (no meat, no fish, but dairy and eggs). Some years ago, I stayed in a hospital and was on the hospital’s vegetarian diet plan. After some days, I got served filleted fish. As I was hungry and had no opportunity to get something different at the time, I ate the whole dish. No problem with digesting the stuff, though the quality of the the excretions where, well, different.

I also ate some dishes containing bacon or ham several times by accident, with no bad effects on my digestion.

Another anecdote (are they data when we collect enough?) - Vegetarian for 6 years, went to Italy and one warmish day gave in to the lure of pannini right there on the street. No problems, although I had heard the same myth and was expecting trouble that never arrived.

I remember a scheme in Sweden to feed killer bears a special meat stew to build up the bacteria flora in their intestines so they would revert to a vegetarian menu.

I have never considered myself a vegetarian but when I lived in England during the 70s good quality meat was too expensive to eat regularly, so my wife and I ate very little. When I returned to Australia, after a couple of years, I ended up detoured to my parent’s place in Canberra on my first day back. My mother, knowing that I hadn’t had a decent steak for years, made BBQ’d steak and salads for dinner. Although all she served me was a steak that I used to eat for breakfast when I was 16 and swim training at 5 AM, I simply couldn’t eat it all.

It took me months before I could eat meat in more than small portions. It was just so rich and lush after years of having very little.

I think changing your diet regardless of the change is going to cause some of those effects. Whenever I start dieting my body will make unworldly sounds for a few days but it eventually adjusts. I’d reckon the same thing is happening, but probably on a more extreme level since going from no meat to meat is a bigger leap than just eating healthier foods. I’d be surprised it if was a permanent thing for the vegetarians.

I’m just curious how this experience went for you. Did it taste just like some new food you never had before? Was it gross till you got used to it? Or did it taste absolutely great? Just curious.

Psychosomatic aversions are very common.

I was a vegetarian for about 12 years, and starting eating substantial quantities of fish with no acclimation period. I had zero problems, but I was incorporating fish into an already-protein-rich diet.

I’ve consumed, by accident, chicken or red meat a few times during that 12 years, admittedly in small quantities. I had no physical effects.

I think it is strongly related to your motivations. I broke ten years of vegetarianism with a huge bacon cheese burger with no problems. But then I had a very good reason for wanting to eat meat again (moving to Africa) and little emotional attachment to vegetarianism- I just didn’t like meat much. That said, these days I eat small amounts of meat regularly, but when I eat a steak, I sometimes end up vomiting- it may just be bad meat though. Who knows?

I had heard, and I confess that I may be wrong with this, that it’s related to the gallbladder. Gallbladders produce bile, which help digest fat. So if you’re used to a low fat diet, which most vegetarian diets tend to be, and then you eat something high in fat, you can have digestive problems until your gallbladder gets used to high fat foods again.

Has anyone else heard of this?

I was a vegetarian for the first 20 years of my life. Now I move back and forth without any side effects. But the first time I ate meat, I did feel uncomfortable and it was very much physiological.

I was a vegetarian for 2 years ( I ate milk and eggs) and when I started to eat meat again, it took me about a week to get my system back to normal.

There was a lot of bloating and such when I went back to meat. But I don’t think I wasn’t digesting the meat, it just takes a few days for the body to readjust

I generally don’t eat red meat, mainly because it doesnt agree with the SO. Do eat plenty of chicken, turkey, and seafood though

If I eat a “large” amount of red meat I can be ill for days afterwards, particularly if its greasy.

So, yeah, I can easily imagine that a veggy could not feel well till they readjusted.

I’ve been a vegetarian for about 9 years. I’ve accidentally eaten a bite of meat a couple of times, and it doesn’t feel good, but it’s never made me ill.

Here are two past threads about this: Raised Vegetarian, Wants to Become Carnivore, and Can a vegetarian from birth become a meat-eater?

In one thread on this subject - I don’t think it’s either of these, but I haven’t found it yet - someone pointed out that even if you never eat meat, your body does digest animal protein because the lining of your stomach is replaced at regular intervals. The lining that comes off gets digested.

I was a strict vegan for a little over one year. I had a change of heart one day, and ate excellent bacon, greasy hamburgers, and a great steak all in one day. I had no ill effects.