As a type 1 diabetic, with a mother who's celiac --- bring what you want! people with issues need to deal with them themselves.
If you want to be nice, bring a veggie platter alongside, or something. But, it really isn't necessary, no matter how hard you try, you can't accommodate everybody.
I bet your colleague eats lots of sugar without knowing it - like in fruit.
Hold your wonderful blueberry muffins up to the screen so I can smell them