Sugar is a sweet substance that comes mainly from sugarcane or sugar beets. When you taste something sweet like a cookie, candy, or ripe fruit, you're tasting sugar. Your body breaks down sugar into energy that powers everything you do, from running around at recess to thinking through a math problem.

The white crystals you might sprinkle on cereal or use in baking are refined sugar, meaning they've been processed and purified from plants. But sugar also exists naturally in fruits, vegetables, and milk. An apple contains natural sugars that make it taste sweet, while a chocolate bar contains added sugar.

Scientists call sugar a carbohydrate, one of the main types of nutrients in food. Your body converts sugar into glucose, which your cells use like fuel. That's why you might feel energized after eating something sweet, though that energy can fade quickly.

People sometimes use “sugar” more broadly to mean anything sweet. You might sugar your tea by stirring in a spoonful, or describe someone's personality as sugary if they act extra nice in an exaggerated way. In old-fashioned speech, “sugar” was also a term of affection, though you're more likely to encounter that in old books than in everyday conversation.

While sugar tastes good and provides quick energy, eating too much of it can lead to health problems like cavities and weight gain.