I met my daughter in the orphanage when she was about 16 months old. They sent her in carrying a sugar coated jelly candy (kind of like Chuckles if you're old enough to remember them). When that candy wasn't enough of a bribe to meet me without crying (she threw it as hard as possible), they came in with a piece of chocolate candy. For the record, she also threw that as far as possible.
The first time I ever saw my daughter eat was in the orphanage on her 2nd birthday. They had allowed me to bring fruit to cut up for her group and those sugar coated jelly candies. They opened the candy to let her have a piece with me, and it was just like a vacuum cleaner sucking it up. I've never seen anything like it in my life....she turned to me, and her little cheeks were stuffed as full as possible, like a little chipmunk. That was also the first time in her life that she'd ever seen whole fruit....it had always arrived to them cut up. She was way more fascinated by the whole fruit than by the candy. When she arrived home, her daycare fed sugary treats for holiday parties and birthdays, as well as m&ms for potty training. Fig newtons were part of the snack rotation, too.
If I were you, I'd wait as long as possible to start giving him unnecessary sugar, since he doesn't already have it and isn't asking for it. For me, my daughter had sugar from an early age, not necessarily introduced by me. Even so, she she still loves healthy foods, and I believe in allowing everything in moderation.