How much sugar should you eat in a day?

On my plan, I am not supposed to go above 24g of sugar in a day. Seldom though I may go above that to 30-35 even though I actually BELOW my already very low calorie intake goal in a day, and even though I eat very very little snacks in a day. What I am finding is that sugar in bread or sometimes even condiments or "healthy biscuits" can add up.

So the question therefore is, is 24g a day realistic for a 26 year old man or is it actually very normal and I'm just not careful enough?