My 3 kids ranged in age from about 9 to 18 when we began eating in the Zone (15 years ago). We didn't have them measure specific amounts, but showed them how to mix and match protein and carb in appropriate quantities by sight, and to always add fat like a small handful of nuts or a small spoonful of oil to a meal, less to a snack. My son was the youngest (a yr or so younger than your daughter is now, so I'll focus on him) and even he picked up on it easily. To help them to make better choices at first, I did not resupply the foods that weren't Zone favorable, as we ran out of them. Instead, I replaced them with their favorite foods from the best choices on the Zone Food Blocks list. My son loved coming home from school and eating snacks like chicken with salsa and a few corn chips, leftover Zoned chili, leftover stir-fry, or a salad (he became a huge fan of salads of all kinds, and still is). I'd pack him a lunch of Zone friendly foods, usually giving him some input as to choices (my two older kids packed their own). If the school lunch was something he really wanted, I'd let him get it now and then. Eventually he didn't want it anymore. Kids can tell the difference, just like we adults can. When you eat only good fresh food all the time, the typical school lunch becomes quite unappetizing after a while. We didn't get rigid about it, none of the "You have to do this” kind of attitude. We simply kept the "bad” stuff out of the house. With mostly Zone favorable foods they liked being the only choices in the kitchen, they got creative (we all did) and discovered all kinds of favorite combinations. We didn't rely on the standard Zone string cheese and fruit snack, or the cottage cheese and fruit snacks either, though they would also be good choices. A tip, take care not to make cheese a habit multiple times a day. It doesn't contain the best fat. Also, we didn’t have any rules about eating out or at friend's houses. Everything was fair game. But, just as with the school lunches, he gravitated to the more Zone friendly combinations. With 10 yr olds, bottom line is, if you don't buy it, they're not going to have the choice to eat it at home. Other kids definitely noticed how he was eating a bit differently. They'd ask him why he didn't eat certain things, and he'd tell it was because they weren’t good for people to eat.
Wow, I’ve been running on here, but you get the idea. Good luck! :-)