No matter what you say or do your parents are not going to make any kind of
diet change until they are ready.  I also have a feeling that most people
who are on an eat what you want diet are just not ready to go to a paleo
diet cold turkey but you might have some luck easing them into a new way of
eating by starting out slowly.  I suggest this.  First step is to only have
food that has one-third of calories from fat.  Simply look at the food label
and if the calories are lets say 100 then the calories from fat can only be
30 or less.  This is certainly not paleo but the idea is to get them to look
at what they are eating.  This will cut out the real icky foods like potatoe
chips, french fries, peanut butter, ice cream and such.  I am not saying
 to
follow a low fat thing, just to first cut out the nasty stuff.  If you can
make it this far then you can eliminate dairy and all of the other foods in
steps.  Best of luck.

JeffS

Oh yah, sardines packed in water make a good traveling food.