It’s all a myth. You do not lose any ability to digest anything based on your diet. Your digestive system doesn’t excrete anything more than marginally different based on your diet. There’s no scientific basis for it. The reason you get sick from the water and food in other countries is because of the parasites and microbes in it not because “you’re not used to it”. Anecdotally I’ve know tons of people that have been vegan (I’ve been myself for 15 years) or vegetarian for years and went right back to red meat with no ill effects at all. Nor should there be.
Meat and fats are far easier for the human body to digest than any plant matter excepting simple starches. If your doctor perscribes a ‘low-residue’ diet for medical reasons you are allowed animal products, other fats, simple starches, and sugars, as all these foods digest well and produce very little waste.
Now, when I was vegetarian for a while (many years ago) I definitely felt physically sick the first few times when I went back to eating meat. And I don’t think it was mental because I wanted to eat it, and enjoyed it… I just got a little queasy. Of course your day-to-day diet influences your digestive tract. We have so many different sorts of bacteria colonizing us, for one thing, and if things are accustomed to processing certain kinds of food, there may be a period of adjustment when you introduce new foods.
But of course it’s ridiculous to say you are ‘unable to digest’ something that has been a dietary staple of most human animals for hundreds of thousands of years.
There was a time when I was eating a pretty healthy diet, when I first got my car and was shopping for myself. I wasn’t a vegetarian, but when I ate meat it was usually lean chicken or something. My diet was probably fairly low in fat and I was eating a reasonable amount of calories. I was almost never eating junk food, and when I ate fast food it would be a small dollar-menu sandwich and sometimes a small fry. I found that if I went to McDonalds and ate a full value meal with a burger and medium fry, I would get sick. I think it was the grease. I could see a vegetarian getting sick if they tried to eat a big steak or something. I always thought it was the because of gallbladder not making enough bile.
What you don’t seem to get is that the people there do drink those same microbes and have no problems. They got used to them. Apparently you’ve never met someone with IBS who can eat at McDonalds but not Burger King. Your body sure does get used to your diet. And if your bowels are sensitive to those changes, it will cause discomfort.
And if their was no scientific reasoning for this observable phenomenon, then that would be a deficiency in the science. Reality shapes science, not the other way around.
Yes there is. Changes in diet can cause changes in gut flora - during the time taken adapting, digestion may be upset a bit. That’s not permanent, of course, or particularly serious, but it’s not mythical or imaginary either.
This was, to some degree, discussed in this previous thread.
You will never completely lose the ability, but you can put your body in a state where it would be very ill advised to suddenly do so in large quantities.
It is well documented that eating a very low-fat diet for extended periods will lead to your gall bladder reducing its function. Sudden intake of large amounts of fat can be dangerous to your health while in this state. I’ve observed more than a few removed gall bladder procedures as a result of this effect.
Additionally long term abstinence from meat supposedly causes your system to shift gears in terms of enzymes produced. This quickly recovers though.
Depending on one’s current diet, as others have already said, sudden drastic changes can cause all sorts of distress, and even damage.
I was going to write this post almost word-for-word. I was a strict ovo-lacto vegetarian from birth. When I was 20, I decided that I didn’t want to impose my dietary restrictions on others, so when I was sent to a training in Dallas and told I could stay with a family there my boss knew, I didn’t mention my diet. The first evening they served pork chops. :eek: It was a bit disgusting to me, but I used a lot of steak sauce and took small bites and was able to swallow it all. I didn’t have the slightest intestinal problems from it, nor from any of the meat I ate thereafter. Before long, I realized that whenever I went to eat with new friends and they already knew somehow that I was a vegetarian, I was disappointed at their willingness to accommodate me, since I had been looking forward to the chance to eat meat guilt-free. Once I realized that, I became an omnivore and haven’t looked back.
It wasn’t food I’d never had before, I was brought up at home on a diet that included meat as my parents weren’t vegetarians. It was a decision I made for myself when I was old enough to prepare my own meals and not have that decision causing problems for the rest of the family.
It wasn’t gross either, it was just “different”. It tasted fine, I hadn’t expected it to be otherwise, although it took quite a while before I was brave enough to have steak!
I think part of the grossness factor involves why you give up meat in the first place. My reason was an objection to factory farming and the way animals were raised in poor conditions simply to fatten them up for slaughter - once it was possible (and economically viable) for me to buy organic meat from local producers, I decided it was acceptable to eat it and decided to go back to a meat diet.
It wasn’t “alien” food, it wasn’t anything I’d not eaten in childhood, so the experience was almost like saying one day I’m not having meat, the next day I am. The biggest surprise was from my friends who’d known for years I was a vegetarian, they were all somehow offended that I hadn’t told them I was giving it up, despite it being absolutely none of their business!
Bile is produced in the liver and aids in digestion by emulsifying fats. It’s stored and concentrated in the gallbladder. The concentrated bile is released from the gallbladder into the duodenum during digestion. Without bile, most of the fats you consume can’t be digested and end up in the feces. You still need bile even if the only fats you consume are from plant sources.
When the gallbladder is removed, bile is released continuously into the digestive tract. As a result, eating a fatty meal can cause digestive problems. I’m about 7 months post-op myself and have had a handful of incidents of digestive upset that might or might not have been caused by lack of bile storage.
The wikipedia article doesn’t mention any dependence of bile production on the fat content of the diet. However, It does note that in addition to it’s digestive function, bile is the route of excretion of bilirubin, a byproduct of the breakdown of red blood cells.
Interesting… is production of bile reduced in cases of iron deficiency anaemia? (which is more common amongst vegetarians, I think)
I don’t know more than what’s in Wikipedia, which doesn’t mention anything on this.
To add to the chorus, I was a strict vegetarian for over ten years.
I recall ordering a mushroom omelette at the peak of my vegetarianism, receiving a western omelette due to language difficulties, and being sleepy enough to shovel a substantial portion of it into my face without looking up from my book. When I realized what had happened, I ended up in the bathroom yakking up.
I found this embarrassing enough at the time, but now that I’ve experienced a shift in values and belief and been omnivorous again for nearly as long… well… it’s astonishing how the brain rules the body.
My second Americorps teamleader was pescetarian, and claimed that trying to eat red meat made her sick after being pescetarian for two whole weeks. Of course, she was also an idiot, so who knows…
Don’t really have anything to add to the thread as far as vegetarianism goes(I’m an avid carnivore), but as far as the above, no. If that were true, we could definitively prove all sorts of quackery(homeopathy, UFO’s, creationism, Miss Cleo…).