All carbs are ultimately treated by your body as if they were sugar - they are all processed into glucose, and your body has to produce insulin to deal with it and restore your blood sugar balance. If you do this too much too often, your body's insulin response starts to fail - hence the enormous rise in diabetes in recent years.
With white carbs, this happens very quickly. With complex carbs, it happens more slowly so you don't get the lows and highs, the 'so hungry I need to eat now because I feel slightly nauseous'. Eating carbs with protein also helps smooth out the extremes.
I eat moderately low carb - I eat whole grain carbs at one meal a day at most. The rest of the time, I replace the carbs with extra veggies or fruit: Greek yog with berries for breakfast, a huge salad with protein for lunch, courgette 'pasta' strips with a carbonara sauce for dinner, etc.
I've lost some weight, which is always pleasing, but mostly I like it because I never feel hungry and have completely lost that 3pm desire to find a flat surface and have a small nap.
Sure, the Atkins-esque myth of a block of cheese for breakfast - of course that's unhealthy. But swapping veggies for carbs like pasta or rice, which have virtually no nutrients whatsoever and are simply cheap bulk for mass production eating - don't see any problem with that at all.