I think it's very hard, once you have bought into LC not to change what you feed your dc, if it was particularly carby before. I have dramatically reduced the amount of bread and pasta my dd1 eats, and she is eating far less sugar.
More green veg, more meat and fish, and her behaviour has changed enormously. She is noticeably calmer, and more serene. Actually how I feel! And it wasn't at all difficult. She hasn't spent a long lifetime rewarding herself with carbs!!
Also, I think people think that because their dc don't eat sweets, they don't get sugar, but they eat a shed load of fruit.... Wich will often have the same physiological effects... I also despair at the low cal advice. Follow the money! You can't sell people broccoli and green bean snacks for lunch boxes!
The IPD cook book arrived, so v excited about trialling some of the stuff. But, it is subtly different to bootcamp, isn't it? Can't think of an example now, but some of the stuff they recommended I would steer clear of, oh yes, lots of butternut squash!