But not all fiber has to have lots of carbs. Celery, psyllium husks (found in laxatives and fiber supplements), greens like lettuce and kale -- all of these contain relatively high amounts of fiber without relatively high carb counts.
I typically eat 3 cups of salad greens, topped with some hot peppers, cucumber slices, and a couple of mushrooms, for lunch, and somewhere between 1/2 and 1 cup of cruciferous vegetables (broccoli, cauliflower, cabbage, etc.) with dinner.
Over the months I've been eating this way, my cholesterol numbers have gone down (in addition, the cholesterol pattern is different and less dangerous) and my blood glucose levels continue to go down. Now, anecdotes are not data, but I'm not alone here in experiencing similar positive health changes with a low-carb/almost-ketogenic diet. That neither proves nor disproves your contention. But there is a basis of scientific support for ketogenic diets. And there certainly is a basis of scientific support for the amounts and types of carbohydrates most Americans eat everyday.