Typically, eating habits are a learned habit. Sure, sometimes they aren't but I can honestly say that most of the times they are.
A perfect example is my cousin, he is picky. Why? Because when he was younger his mom only fed him easy stuff like hot dogs, pickles, apples, other easy to give fruits and fast food. My uncle would try to introduce new foods but he wouldn't try them. He is getting better, but it's been difficult.
Another example is my oldest daughter. She LOVED butternut squash and would gobble it up whenever I would make it for dinner, that was until one night we were at dinner with my grandparents and my cousin was there. My nana made butternut squash, my cousin said he didn't like it and just like that, my DD "didn't like it". Thankfully, she got over that quick.
As parents it is YOUR responsibility to teach your children proper eating habits. If YOU eat like shit, chances are so will your kids!