Meals need wheels!

Why is it that no matter what meal I put in front of the girls, if it's a normal typical (good-for-them) meal, they take 30-40 minutes to eat them?  Or, rather, make some semblance of an attempt at eating, playing, and butchering it???  Then, when they get a "junk" meal (e.g. McDonalds happy meal, pizza & fries, etc.), they wolf it down like they haven't been fed in months?  It drives me crazy!  It's always worst when we have to go do something right afterwards, so this tendency drives me BONKERS.  I sure hope it's a phase because I'm getting sick of eating my meal, prodding them to eat theirs, getting out random things that need to be done while they're still eating, completing them, prodding them some more, and literally ordering them through each step of the process (e.g. "Pick up your fork, put food on it, put it in your mouth, chew, swallow").