The yeast eat the glucose in the sucrose which means what's left is fructose. Depending on how much sugar you put in yours and how much you drink, it might be a problem, might not. 1 cup sugar (200g according to nutritiondata.self.com) per gallon translates to 1.56 total sugar per oz before fermentation. 0.78g per oz fructose, plus whatever glucose is left. In a 10oz serving, 7.8 (let's call it 8) grams fructose, plus maybe (guessing) 0-3g glucose. So 8-11g total sugar every other day, you should be fine. FWIW most studies show that it takes 50-60g of fructose per day to start showing negative metabolic effects.