well, in most cases it's to do with your status isn't it? If you're from a poorer background your family tend to eat less healthily, well that's how it is round here, you only ever see chavs in the chip shops round here, mainly cos they're skaaaaanky!
That and the fact that junky foods are cheaper than healthier choices etc, and there's just not enough info readily available so when you get to the stage of being pregnant and your midwife isn't trying to get you to sort your diet out cos they think you're a lost cause either way, then how is anyone meant to change?
I am only going by the way it's done here, and it's actually meant to be quite a well off place to live here, but everywhere has it's poorer areas right?!