The substance that most candies contain in high amounts is **sugar**. Sugar is a primary ingredient in candies, providing sweetness and enhancing flavor. It can come in various forms, including granulated sugar, high-fructose corn syrup, and other sweeteners. In addition to its taste, sugar contributes to the texture and mouthfeel of candies, helping to create the desired consistency for chewy, hard, or gummy varieties. However, the high sugar content in candies raises concerns about health issues such as obesity, diabetes, and dental problems. Moderation is advised when indulging in these sweet treats.