I'm going to need some perspective here. Are we talking about Mountain Dew in a baby bottle, or cheap chicken in BBQ sauce?
Mountain Dew first. As a general rule, if it comes in a bottle, don't put it into one. This handy maxim covers soda, beer, Scotch... (why would you waste good Scotch on a baby, anyway?) Soda is never acceptable in a baby bottle and you should feel free to say so. You can defer any animosity by quoting me. I don't feel like I'm going out on a radical limb here, but based on a recent, highly scientific study at 7-11, I can attest that this practice is still exists.
The cheap chicken is another matter. I'm proud to say that my family eats only organic meats and produce...except when it is too much of an inconvenience or too expensive. Before you call Child Services, I'm going to break the Shiftless Mommie template and post a second picture. This is the entire organic section of our local grocery store:
Notice that despite the relatively high percentage of croutons and salad dressings, there is no lettuce. (By the way, extra points for anyone who can identify my grocery store based on the ubiquitous, eco-font sign.) Also, that 4-pack of apples will last my family approximately 3 hours and it costs $5.00.
So I do what I can. I have a great organic buyers' club, but there are times when it's 7 pm on a Sunday and Mother Hubbard has to run to the local market, where I curse cruel fate that it's easier to find size 8 shoes on the second day of a sale than a gallon of organic whole milk. I think a lot of people find themselves in similar positions, and you should be careful before modeling for your child that the way to make friends and change minds is to point out how people aren't living up to your standards. An occasional piscine cracker or convenience store banana isn't going to turn your Mogwai, and it shows that you appreciate generosity from others.
And, of course, there is alway the possibility that any sanctimonious lecturing will backfire. If the internet has taught me anything (besides what men really want and how to properly roast chestnuts), it is that no matter how fanatically crazy you are, someone else will always be crazier. Imagine the embarrassment when your child's organic, gluten-free cupcake is rebuffed by a raw-food, local-based, fruitarian classmate. Why do you want to inflict that on someone else? Why start a gastronomical arms race? Keep in mind that when you aren't looking, your kids have probably been eating unspeakable things, especially if you have pets. (Don't think about that for too long.) It is ok, nay, necessary to relax sometimes and let them play at a friend's house without an emergency kit of natural almond paste and edamame. (Not to knock edamame. It's delicious, which is why I'm glad my kids don't appreciate it yet.)
When we start food-policing, we set ourselves up for failure. When failure is inevitable, we just give up and go to McDonald's. Fifteen years later we land in
To answer your question, it's not rude, per se, to tell someone that you don't want your kids eating the marshmallow yam casserole; it's just not a wise investment of your time. Give them a good base of healthy food and then let them occasionally and graciously try Fruit Rollups. You may be pleasantly surprised. I finally got to go to Busch Gardens in high school and it turned out that I preferred Colonial Williamsburg. That's why I'm so fun at parties.
Are you going to go see The Grey?
No. Movies like The Grey perpetuate the destructive myth that being stressed is the same as being entertained.