There is no such thing as an "essential carbohydrate."

Generally, lower carb foods are higher in essentials; protein, fat, micronutrients, vitamins, and amino acids. I do well with the very low carbs in salad greens, but I also handle carrots and onions and low sugar fruits like berries, for satiety and nutrients.

There are folks who struggle if their carbs get too low, as though their body is not able to get into deep enough ketosis; I have seen it in myself, when I got really sick and had to change the way I ate.

But if you are doing well, then it is nothing to worry about.