How much sugar should be consumed in one day?

Sugar is not essential and therefore there are no existing recommended daily intake. So you shouldn't consume any sugar per day.

Some say you should consume 80 grams per day, but the white sugar that people generally refer to as sugar adds no nutrients to your body, so there is no real reason to eat it at all. There are natural sugars in fruits and other types of sweeteners, like honey and stevia, that do have nutritional value.