According to wired and some other posters, carbs should only be introduced when the person is ready and can handle them.
These people will never know when that magical moment occurs because the high fat diet they're on makes them glucose intolerant, hypoglycemic, and insulin resistant.
Everytime they try to introduce carbs they're going to have symptoms and therefore claim that carbs are bad or that they weren't ready for them, which is a load of crap.
Carbs are necessary for energy and brain function. Restricting them causes all sorts of problems as mentioned above.