They could always find healthier sources for fries. There are plenty of varieties in Bolivia—blue, purple, red, etc. Then sweet potatoes are growth in the South quite frequently (the South of the United States that is).
One local store has all sorts of varieties of potatoes from all over the Americas. Maybe McDonalds can use this opportunity to introduce something new, colorful and healthier. But then again, plain white is what the management wants.
There are only certain types of potatoes that give you the specific McD French fry…it all depends on water/sugar/starch content