First, many nutritionists have no clue. Their thinking is, a steak has a ton of nutrients, so you should eat steak.
Second, your body needs carbs, just like it needs fats and protiens. Depriving yourself of any one of those is not natural and is a form of starvation.
A low carb diet is not needed to loose weight, a LOW CALERIE diet is needed. Just eat modest portions of healthy foods and you will do fine.