It is a well-known fact that there are many kids that won't eat anything green, spicy, or 'weird'. This might be based on their genetics, such as that they have specific alleles for tasting bitterness that some people don't have. With age, we get used to it and the genes matter less.
However, I think most kids today stick to bland, mass-produced factory food because their parents feed them that kind of food, out of convenience and influenced by advertising. McDonald's burgers (with no lettuce and tomatoes on the kid burgers, mind you!), french fries, chicken nuggets in a heat up plastic box, poptarts from aluminium foil packets, neon-colored 'cereal' with marshmallows, all soaked and dusted with fat, salt and sugar, oh the compounds we humans love!
And, it certainly doesn't help that most parents eat such food too, so they are not providing a home environment with real cooked food and a variety of ingredients. Many parents just take the easy way out - why force Bill to eat broccoli and have a scene at the dinner table? "Frozen pizza is so great, lets have it for dinner", again.
So, it is absolutely no surprise to me that a big food experiment with school lunches in Los Angeles failed. (read the news story here) They changed the menus to include more vegetables and healthy food, such as new dishes such as veggie curry, jambalaya, and pad thai (Mmm...). Now, my kids love those three things, but I don't think most kids do. Actually, I know most kids don't. In the test program, the schools got rid of chicken nuggets, nachos, chocolate milk, and other fast food calorie-bombs. The kids hated the change, many refused to eat the new food and just threw the food in the garbage. Undercover food snack deliveries started, and it was just a giant flop.
I am not surprised at all. First, these kids probably never or rarely had healthy food at home, at school, at restaurants or anywhere else. They are brought up on the bad stuff, and their parents eat the same thing. Unless you get the parents with you, and start this early on it will not work. I guess the only exception are those weight-loss boot camps where there is no alternative, "either you eat this or nothing, and there is just desert around here so you better eat here".
Second, if you are in middle and high school, there is giant psychological tension at all time, and especially in the cafeteria. Eating something weird, or not eating something, can easily turn into a trend, a thing to be teased over, or just something you don't want to deal with. Cliques of popular kids can very likely influence loads of kids not to eat something strange.
Third, in the schools, why was the left-over food thrown away? Give it to some pigs if it is leftovers from kids' plates. Keep the pigs outside the cafeteria, and tell the kids where bacon comes from! If there are left-over food from the kitchen, pack it up and give it to soup kitchens, hungry Occupyers, disabled vets, or anybody else that needs some great, fresh food. (This idea came from VFK when we talked about this.) If the food could be thrown away like that, then they also have a bad recycling system at the schools.
Fourth, if you really want people to change giant habits like this you to have to make it relevant to them. It has to be personal, not imposed by Big Brother, and it has to feel like an option, not a must and something a teenager has to rebel against. Use it as a teaching moment, without them realizing it is educational. Have cooking classes with parents plus kids. Do survival courses without any cooked food, with foraging from basic ingredients only. Grow the food on the school yard, plow up all that useless grass. Make the football team dig potatoes by hand for exercise. Keep bunnies, chickens, and pigs. Eat weeds. Cook cultural dishes from around the world, and cook ethnic 'fast-food' like dishes. Spaghetti with sauce, tacos, hamburgers - these can be great and good!
If I could decide, certain foods would be outlawed, and there would be no food advertising in TV (or anywhere else) for kids under 10. And no fake infomercials either. Everything would have 50% less sugar in it (if it had any to begin with), and no cereal would have food coloring. Everybody would have to intern at least 2 months on a farm, in a bakery, slaughterhouse, kitchen, or something like that before they end high school, to understand where food comes from and how it is made. (Actually, interning at a hamburger patty factory might not be bad. Might turn you off hamburgers forever. ) And kids should visit farms all the time, from the time they can put their fingers in their mouths and say gaga over sheep and apples. Chicken nuggets and other super-processed machine-made food should have giant warning labels on them, saying "NON-FOOD FACTORY PRODUCT".
In the end, I think this is of course a societal problem, but it really comes down to the parents. If the parents don't care about food, and the food for their children, then the kids will not care. If parents give in and are laissez-faire parents (=letting any little kid decide for themselves all the time), then you get kids that are whiny, picky, irresponsible, selfish, and won't eat any anything real and interesting. And who wants to live with such a person when they are adults?
Of course processed fast-food taste good, it is made to make us love it - it is all part of the commercial plans to sell more and to earn more money for the companies. But you don't have to buy into it. As a parent, stay strong, and if you slip now and then, that is OK. I have given my kids Hungry Man TV dinners, mac and cheese from a box, Spaghettios from a can, and so on. At the time, it was what I could handle, because of other circumstances. But now they eat nearly everything (well, one is a vegetarian that eats fish, and neither eats beets, which is perfectly fine).
It is never too late to change, to try something new. But to dare to try, I don't think you should be in a giant high school cafeteria and be served lukewarm sticky jambalaya surrounded by other teenagers that tell you it looks like "you-know-what"... I think this whole food movement would work better if people knew how to cook better, so maybe that is where things should start. With a knife, a pot and a cutting board. Maybe we should have survival courses in the kitchen. "How to cook from scratch during 5 days without electricity and a functioning fridge", hehe... Well, we don't have to be that drastic to begin with. How about "How to cook from ingredients that come in boxes with less than 3 ingredients listed on each box"?
(And a caveat - there are exceptions of course, but I think everybody can eat better. Being 3 years old is no excuse to live on only 4 types of food.)