Just wanted to add that this is exactly what I did as a child: Right around my 12th birthday, for various reasons, I decided to go vegetarian. After disbelieving me at first, and then pulling their hair out a bit, my parents did support me and I am still a vegetarian today, fourteen years later. So, it can be done. The advice about proper nutrition preceding my post in this thread is all spot-on.
My girlfriend is like that and she’s fine and enters the London Tri-athlon every year. now we live together I’m about 90% vegetarian and there’s plenty of nice food to eat, though I’d question whether it’s a sensible choice if you don’t really like vegetables. I’m also not sure what the state of American cheese is these days but in Europe we have an extensive and delicious selection of cheeses that make getting animal protein a pleasure.
There’s no harm in doing your research but as long as she’s eating sensibly it shouldn’t be a problem. Afterall it’s just as easy to eat a shitty diet when you eat meat, maybe even moreso if you like fast-food.
And as an aside: People who eat fish aren’t goddamn vegetarians, they just don’t eat meat. I don’t eat fish, that certainlyy doesn’t make me a vegetarian. And if you eat fish but not meat for moral/ethical reasons then I suggest you do some research into fish stock depletion and reconsider whether that’s valid.
See I knew if I asked here, I’d get a good sampling of opinions before I go floundering about on the Internet looking for info.
My daughter claims her reasons for wanting to be a vegetarian are ethical but she’s always done pretty much the opposite of what her friends do so I have a suspicion that her desire to be unique is part of her motivation as well. Either way I need to support her.
All the advice to involve her in the process and help with the extra work is great. She does like to cook so if she’s given control over what she eats and how it’s prepared, hopefully she’ll start making sensible choices.
The whole thing has become even tricker by the fact that her twin sister appears to be lactose intolerant. Once I’ve determined for sure that is the case, meal prep is going to have to become more organised than it has been. My trainer also wants me to follow a low glycemic index type of diet, which although I’m not completely sold on it, will add yet another layer. It’s getting harder to just grab something out of the fridge and throw it on the table!
Thanks for all the useful advice so far.
Complicated “complete protein” schemes have largely been refuted. There is no need to stress about getting a complete protein in each meal. Anyone eating a relatively varied diet is going to get more than enough protein, and protein deficiency is extremely rare even among vegetarians.
When people say that meat is high in protein, what they really mean is that meat has complete protein. There are a variety of amino acids (the building blocks of protein) that we need to get from our diet, and meat has significant amounts of all of them. Most plants fall short in a few amino acids, but the key is that not all plants fall short in the same ones, so you can still get complete proteins from plants, just not all from one plant. The most common combination that gives them all is rice and beans, which is why that’s a staple food in so much of the world. In fact, you could eat nothing but rice and beans for every meal and have nothing to worry about nutritionally, beyond boredom.
You say she doesn’t like most vegetables, and that definitely needs more specifics. If she doesn’t like beans (or peas or peanuts), then it’s going to be pretty much impossible for her to go vegetarian. There are a wide variety of healthy vegetarian diets, but so far as I know, all of them include some sort of legume.
Also, the “not liking vegetables” may just be a function of how they’re cooked. Many folks’ only experience with vegetables is overcooked into flavorless mush, which isn’t even all that healthy, either. You and she both should experiment with cooking vegetables in different ways to see if you can find something you like (steamed, stir-fried, and raw are all options you might try).
It’s true that you don’t need a complex of complete proteins in every meal, but you do need proteins that contain all of the essential amino acids in a diet. And even though a variety of sources will provide complete proteins, the density of those proteins isn’t very high in many vegetable sources, requiring that the vegetarian eat more bulk of food (and typically more carbohydrates) to get the right balance of proteins. What comprises a “protein deficiency” is arguable, but it should be noted that few if any athletes follow a strictly vegetarian diet specifically because of the low balance of proteins, and many require protein supplementation.
They body will synthesize lipoproteins (cholesterols) even if you consume cholesterol, but developing children may need additional dietary sources of cholesterol to support growth. Dietary cholesterol also has some poorly understood influences in the production of hormonal sterols and transport of some fat soluable vitamins. There is no question that you can live without dietary cholesterol, but it isn’t clear that it is more healthy to do so, especially during childhood development.
Agreed…and the reason why many American vegetarian diets–which are often startchy and have little variation–are particularly unhealthy. Again, the same can be said about American (and Western) diets in general.
I think I mentioned that before; children need essential fatty acids (as do we all, but moreso during development or strength training). There are also some indications that children need some amount of saturated fats, and nobody really needs trans-isomeric fats found in fried foods and highly processed food.
Stranger
Yes, but for many Americans high bulk/low calorie is arguably what they need most. kbear mentioned her daughter is a bit overweight, so increasing dietary bulk might help her take a few pounds off.
If we were hunter-gatherers or subsistence farmers that might be more of a concern, but most of us are pretty sedentary these days. If the kid is an elite athlete that’s a different matter, but if she’s not, probably not a problem. If she takes a few pounds off she might even wind up being more active, which is all to the good.
I became a vegetarian at 14. I’m fairly certain I turned out fine - I lost a lot of weight and my skin cleared up, but that was most likely due to just growing up rather than a change in diet - and I’ve never had any health problems due to not eating meat.
My mother very rarely cooks me any meals, it’s only when the rest of the family is eating vegetarian that I get a meal cooked for me. The condition of me going vegetarian was that I cooked all of my own meals.
I’m 20 now and feel sick to my stomach at the thought of going back to meat - I would say make sure she’s eating healthy and not going to get sick from lack of nutrition, and then be supportive. Sometimes it’s difficult for meat eaters to understand vegetarians (I’m not saying that’s the case with you, but it was with my parents) but as long as she’s not eating one piece of bread and a single potato a day, the switch can work out fine for everyone.
coughEGGScough…
Why would kids that age want to go vegetarian?
It doesn’t seem like a decision a kid her age would make.
Do you know any young teens? God, all the time with the “meat is murder” and the “save the whales” and the “you really shouldn’t drive after that one beer” and the “you’re not recycling that?” and the “you eat VEAL?” and on and on and on and on.
I’ve been a vegetarian my whole life, and it doesn’t seem to have hurt me; then again, I’m from one of those traditionally lacto-vegetarian Indian cultures, so presumably I’ve grown up accustomed to a diet crafted to supply proper nutrition without any meat; perhaps one who grew up with different dietary standards would need to think more consciously about how to adapt.
As others have said, my understanding is that full-on veganism is much more difficult to make nutritionally sound, and pretty much requires supplements.
No, not really but she’s not even a young teen yet!
Damn, I’m only 24 and I’m already an out of touch old geezer!
Al Bundy is correct. I just had a can of tuna for supper, so I ran up and grabbed the can and checked out the label: zero fat of any kind.
This. I became vegetarian around that age. It was purely out of love for animals, and because I didn’t particularly care for meat, anyway. I have heard form quite a few friends that being vegetarian or vegan was pretty much a convenient way to frame their eating disorders, but it could just be a simple case of meat = wrong.
Amazing advice here, overall. I see iron pills in her future. You might also want to get her one of Michael Pollan’s books or have her visit a local family-run farm, if there are any nearby. Learning to cook for herself (and the family) is a must – you might even be able to convince her to eat eat one or two days a week. Especially if that meat is bacon.
Agreed, provided she’ll eat vegetables rather than a bunch of carb-loaded starches and sugars, as the o.p. mentions.
The o.p. herself mentions a lack of knowledge about how to constitute a healthy vegetarian diet for an adolescent. It is not unreasonable to obtain professional counsel from a qualified source in this matter (as opposed to asking the personal opinion of random strangers on the internet). Certainly “billions of people have manage to eat and still eat without needing professional services,” by following traditional and varied diets, but the typical American view of vegetarianism–consisting largely of rice and beans, pasta and canned tomato sauce, TVP, boiled or fried vegetables, and those bland and nearly nutritionless veggie burgers–isn’t anything like a balanced diet.
Sure, if you don’t object to eating chicken abortions or the cruel and inhumane treatment of farmed poultry. 
Stranger
Nah. Otherwise there wouldn’t be cultures that are vegetarian even long after they’ve become wealthy enough to afford lots of meat. It does require more planning if you’re used to eating meat.
Good point about the control issue.
TBH, even if she does continue eating meat, her dislike of vegetables could be a problem. But you’re absolutely right to be concerned - some vegetarians do end up eating crap.
Basically, you can compromise. She wants to be veggie? Fine, but she has to ensure she’s eating healthily and she can’t expect you to go too far out of your way to accommodate her. Like, substituting nut cutlets for a meat joint would be easy enough. Make a stew and either add the meat in after taking her veggie portion out, or put her veggie portion in a different pan while the meat stews with the veggies in another pan.
Whereabouts do you live? Is it easy enough to get things like nut cutlets and hummus and so on? Hummus is really handy for sandwiches and for making veggies more appetising, and is a great source of protein.
My ex-GF’s sister became vegetarian at 12, and her Mum was quite against it, so her Dad decided to view it as a challenge. Since then (20 years ago) he’s got really into cooking, and the whole family eats vegetarian food by choice sometimes even though only two of them are veggie. It genuinely became an opportunity to try new foodstuffs and cook together.
I went veggie at 12 and it seems to be a very common age indeed to make that choice, especially for girls, though it doesn’t always last.
For a while I ate absolute crap, but, TBH, my meat-based diet wasn’t exactly healthy either because my mother can’t cook and I lived on takeaways and crisps, so removing the meat meant taking the beef patty out of the burger.
I’m going to have to start calling them chicken abortions now. I love me some chicken abortions!
So… they’re fine with the little bean fetuses ripped untimely from the womb of the mama bean? Just checking.
ETA - I’m 30, and I still call gherkins “fetus pickles” because it grosses my mom out. 
Man, so a few weeks ago I had nothing in my fridge but chicken abortions, a tiny slab of cucumber, some blue cheese crumbles, green and white onions, and was starving. I was too lazy to put pants on, go outside and have someone make me food, but I didn’t have any actual food at home. Then it hit me: Omelet! Man, I love chicken abortions. They do so much!
Sorry, I have nothing to contribute here.