That's like saying crystal meth users can just quit. Crap food is engineered in a way that highjacks feedback loop and makes a human dependant on it. Education is important but absolute majority would not stop eating while stating in the mirror or at the scale number. 

On top of all that, being unhealthy is actually trendy now, as it seems. Everyone around is obese, unhealthy and with chronic disease. Being healthy = fringe minority. 

It's all about "me me me and how dare you judge me for my poor choices." 
Half the shit manufacturers use in food production is straight up banned in Europe. Think about that for a bit. 

 Except crystal meth and food are not even remotely on the same level at all.

BTW I'm not saying the abuses of the food industry shouldn't be stopped, I am though saying that the person needs to want to stop abusing their own body if they really want to quit. And yes, that goes for Mr Meth as well.

I don't have the perception that being unhealthy is a trend now, but dystopically enough I also don't find that hard to believe.