Firstly, low carb does not mean no carb, that is, you can still have carbs, but also regulate the amount. Secondly, there is no essential carb. It means that a person can survive without a single gram of carb in his/her diet.
We eat fruit, but we choose nutrient dense fruit such as for instance berries, but steer clear of high sugar tropical fruits such as mango, bananas and pineapple. When we do eat carbs, it is from nutrient dense lower carb vegetables, nuts, berries and dairy. Our vegetable intake for most people actually increases. We remove the processed carbs from our diet and replace them with increased vegetables. We no more use carbs contained in rice, pasta and bread.