Which also got me to thinking- should you have the right to insist on vegetarian/vegan food? Not only is it more expensive and more of a problem to provide, but you are a tool of the army, and you probably do your job for them better when you get enough protein.
This is kind of a sick comment, but I had to share since you reminded me about it with your observation:
I worked as a consultant for AmeriQual Foods for a little while...they're one of the main suppliers of MREs to the DOD. While I was there, I saw a dude accidentally cut most of his thumb off and bleed into a vat of food. A few of the workers SWORE that they still packaged the food and shipped it out...although, based on my experience with the company, I find that very hard to believe. It was probably just grim factory humor.
One of my best friends also worked at a company that supplied temp workers to AmeriQual. Not too long after 9/11, they had a scare because terrorists were supposedly trying to infiltrate their temp workforce (allegedly after finding the corporate address on MRE packaging that was improperly discarded.) I don't think anything ever came of it, but my friend was going crazy because of all the extra paperwork.
It's already been suggested that providing vegetarian meals is a logistical nonissue. (Canadian soldiers are also entitled to Kosher and Halal meals, and I can't imagine that that's uncommon.) But it's easy to imagine military professionals arguing the opposite. Logistics, tactics, and esprit de corps are used to justify several kinds of bigotry and obstinacy in Western militaries. It seems to me that, as a rule of thumb, legitimate military concerns do not easily justify lower standards of tolerance, human rights, or, (as Julien Assange will agree) openness. Canada has rejected at least two of these arguments experimentally by allowing openly gay service members (unlike the US) and by permitting women to serve in every trade (unlike the US and the UK).
Also, the whole vegetarian "protein deficiency" thing has been pretty thoroughly debunked, unless you only eat potato chips. It's surprisingly difficult to eat a diet that won't give you at least a minimum of protein without dying from e.g. pellegra or beri-beri first. (Maybe not enough protein for hardcore bodybuilders, but certainly enough to live well.)
I ate a vegetarian diet for seven or eight years, a vegan diet for a few months* along the way, and have had a primarily* * vegetarian diet for years since then. I give blood regularly (I'm AB+, a rare donor blood type), and I've never, ever, ever had a problem with low iron - it's usually been quite high. While that's only one data point, it seems consistent with what I've read about nutrition - problems mostly occur when people give up meat but still eat a rather monotonous diet. ("In other news: Eating nothing but twinkies and whiskey is bad for you...Film at eleven.")
* I'm a cooking geek, and was interesting where those constraints would lead me.
* * same, plus fish and occasional Italian and French/Vietnamese charcuterie (Bánh mì!), but I cook/eat vegetarian by default.
hence, you should have no trouble. :)
Besides: Lentils, spinach, and broccoli have iron. How many vegetarians don't eat at least one of those regularly? (Other cliches: vitamin B-12 - Vegans might have a problem, vegetarians are fine. Calcium - "Dark green leafy vegetables". Do vegetarians eat those? Oh. Wait...do carnivores eat those?)
This is, of course, because fish is just a specific kind of meat, so nutritionally it's not vegetarian in the slightest.
For years I was a vegetarian + fish guy. I hate pork, my family boycotts lamb, and I didn't have a taste for beef. Nowadays I eat the token hamburger every few weeks, because I've noticed I feel a lot better for it.
That being said, there's usually a vegetarian meal in every box of MREs.