I also don't eat sugar, and it's a choice, not an allergy or diabetes. Like your friend, I just feel better when I don't eat sugar. (If I go into detail it involves descriptions of my bathroom habits and lady times.) My daughter has also reduced the amount of sugar she eats. Her clarinet section leader last year used to bring in treats to sectionals, and she'd bring an apple for my daughter, which we thought was so sweet! (sweet as in kind, not as in sugar!)

There is a huge difference between fruit sugars and refined sugar or HFCS. Fruit sugars are bound up in soluble & insoluble fibers, which creates a sort of time-release effect in the gut, so that the sugars aren't all released at once and you don't get that sugar high and sugar crash and the insulin surge. That insulin surge is pretty much toxic!

I realize your event is probably already past, but for anyone, go ahead and make your sugary treats, but if you know of someone who doesn't eat sugar, just bring fruit for that one. They'll really appreciate your kindness.