Anecdotally, I completely disagree. I've been eating a ketogenic diet (less than ~20 net grams per day) almost exclusively since May 2013 and have been lifting for the last 8 months and haven't needed for any carbs. While it's possible after a certain level some well-timed carbs can help you lift heavier than without, those won't be the kinds of sugars most people are eating. But, since I'm not looking to become a body builder I'll probably never need to worry about that.
Well, you have to admit that a ketogenic diet is something else entirely. That is impressive, I personally don't know any people who could stick to it for such a long time.
