• 砂糖さとう — granulated sugar
• 糖分とうぶん — sugar content
• 乳糖にゅうとう — lactose
• 果糖かとう — fructose
• 糖尿病とうにょうびょう — diabetes

糖 is a 形声 (keisei) character made from the radical 米 (rice) and the phonetic part 唐 (とう). 米 signals sweetness or grains; together they point to sweeteners derived from grains or plants.