low carb vs low fat diets

Hello! I have a question about low fat diets. I always in the past had great sucess with low fat diets. In August of last year I had my gallbladder removed and my doctor had told me that if I wanted to lost weight try to cut out carbs because the low fat diet would not work anymore. ( I was on it to calm my galbladder down for removal) I wonder sometimes if the No Carbs thing is just a "new diet way" Since I remember how popular the Low Fat diet was in the early 90's. Is there much of a difference?