Most ketoers eat high fiber, low carb, nutrient dense vegetables. Non-digestible fiber is listed on the food label as a carbohydrate, though it doesn't enter the blood stream - so ketoers are concerned with 'net carbs', not total carbs.

If you keep your incidental carbs low enough, they will be burned off without taking you out of the ketogenic, fat-burning state.

It is not the incidental carbs in these vegetables for which we might have a nutritional need, but the vitamins and minerals.