Good Calories, Bad Calories
may not be all it's cracked up to be either.
(not sure the links are w/f/s, use caution as always)
I don't think anyone except the FDA is recommending a diet based on 60% carb. intake anymore. But carbs get too much of the blame. They play an important role in performance.
If one is a desk jockey, carb demands are low, just as caloric demands are low. If someone is an olympic swimmer (Michael Phelps), carb demands are high just as caloric demands are high. Weightlifters, not a ton of activity, but a solid amount of stress, caloric demands should meet whatever it takes to stay in a weight class, probably not much room for carbs.
This is all assuming people are getting their protein of course.