no matter what advertisements they see and no matter what you are surrounded by, your child will follow what your family's food habits are. we are not a fast food family. dd does not crave fast food. we are a cook at home, whole food family with loving eating out once in a while at tasty restaurants.
however of course kids love sugar.
dd wanted lucky charms cereal for a long time. i got her some one year.i think she was 4 or 5. yikes she hated it. one bowl was all that was gotten out of the box before it was tossed. taught her a big lesson. advertisors lie.
from around 4 to 6 i gave into some of her wishes that she had due to advertisements. i didnt have to 'teach' her anything. that is when she learnt advertisers lie. and what you see is not what you get.
for me what has worked is having dd bombarded by teh ads. not that i am purposefully doing it but we always seem to see a lot of tv socially at someone elses house or as you pointed out everywhere else.
by 8 dd had gotten a sense of healthy and balanced food.
we buy local so dd knows the 'taste' of food. we have gotten yummy looking food and found they werent as yummy as the pictures foretold.
dd does ask for junk, just like i do. we have both talked it over and decided that a little junk is ok. so once in a blue moon dd gets a couple of ounce of soda. chips.
however of course at a ball game she will go for the cotton candy. eat a bit and be done with it.
the key is we eat healthy at home. dd is used ot the style we eat. when she goes for junk most of it she rejects because she knows hte 'real' taste of food and finds the junk too chemically tasting. what worked for her was me NOT saying NO but giving her a sample. she is that child who had had complete freedom to eat her halloween candy but after the first day or two, she ignores them.
by the time dd was 8 she was in complete control of her food.
between the ages of 2 and 5 we ate out a lot. which kinda worked in our favor because we ate at local eateries. that developed dd's palate so that she doesnt long for crap. now how many children would you find who hates pizza, pbj, hamburgers but loves sushi and vietnamese and thai food. ANd loves cooking herself and actually enjoys it.
ETA : we are a RARE fast food eating family. mostly mexican food. even when I ate french fries and offered dd she didnt want any. however she LOVES chipotle vegetarian burrito.