No sugar No carbs. Is that a good diet?

Not really. You need a well rounded diet with protein, fats and carbs. Complete absence of carbs is not a good idea. Try well rounded diet with normal total calories for your weight and daily exercise.
No need for sugar. There really is no need for sugar or sweets in our diet. Our body can make its own sugar as needed. A low carbohydrate diet can be very satisfying and safe, with carbohydrates coming from vegetables and small amounts of fruit, occasional whole grains.
Try not to be so. Restrictive, as this type of diet will be quite difficult to follow for any prolonged period of time. Also if you are very active, no carbohydrates is not ideal. You may want to focus on carbohydrates coming from whole grains. And if you are consuming simple sugars, best if they come from fruits.