Calories
Sugar is 100% simple carbohydrate with 100% empty calories with no nutritional value whatsoever. On the extreme side, Water is the only known consumable with Zero calories and Zero carbohydrates.
It is not that calories are bad. Calories are the cost we pay to get something in return. That 'something' has to be nutrition that our body requires for healthy living. The nutrition we need should come in the form of protein, complex carbohydrates, vitamins & minerals.
So, don't let anyone tell you that Calories are bad.