refined sugars have negative effects on everybody.
people (of all ages) who are more prone to sugar reactions (hyper, yeast overgrowth, sugar highs and lows) should especially avoid it. pre diabetic conditions can be passed down through generations.
sugars that naturally occur in fruit are better for you, but do have the same effect on the body as refined sugars. sugar.. is sugar.. is sugar. its all the same to the body
keep in mind too that bread, pasta and the like converts to sugar in the body.