Carbohydrates: How carbs fit into a healthy diet

Carbohydrates aren't bad, but some may be healthier than others. See why carbs are important for your health and which ones to choose. By Mayo Clinic Staff

Carbohydrates often get a bad rap, especially when it comes to weight gain. But carbohydrates aren't all bad. Because of their numerous health benefits, carbohydrates have a rightful place in your diet. In fact, your body needs carbohydrates to function well. But some carbohydrates may be better for you than others. Understand more about carbohydrates and how to choose healthy carbohydrates.

Understanding carbohydrates

Carbohydrates are a type of macronutrient found in many foods and beverages. Most carbohydrates are naturally occurring in plant-based foods, such as grains. Food manufacturers also add carbohydrates to processed foods in the form of starch or added sugar. The most basic carbohydrate is a sugar molecule, which joins together one or two units of carbon, hydrogen and oxygen. Other carbohydrates contain three or more units of the carbon-hydrogen-oxygen trio.

Common sources of naturally occurring carbohydrates include:

  • Fruits
  • Vegetables
  • Milk
  • Nuts
  • Grains
  • Seeds
  • Legumes

Types of carbohydrates

There are three main types of carbohydrates:

  • Sugar. Sugar is the simplest forms of carbohydrates. Sugar occurs naturally in some foods, including fruits, vegetables, milk and milk products. Sugars include fruit sugar (fructose), table sugar (sucrose) and milk sugar (lactose).
  • Starch. Starch is made of sugar units bonded together. Starch occurs naturally in vegetables, grains, and cooked dry beans and peas.
  • Fiber. Fiber also is made of sugar units bonded together. Fruits, vegetables, whole grains, and cooked dry beans and peas are among foods that are naturally rich in fiber.

More carbohydrate terms: Net carbs and glycemic index

You may see terms such as "low carb" or "net carbs" on some products, or promoted by some diet programs. But the Food and Drug Administration doesn't regulate these terms, so there's no standard meaning. Net carbs is typically used to mean the amount of carbohydrates in a product excluding fiber or excluding both fiber and sugar alcohols.

You've probably also have heard talk about the glycemic index. The glycemic index classifies carbohydrate-containing foods according to their potential to raise your blood sugar level. Many healthy foods, such as whole grains, legumes, vegetables, fruits and low-fat dairy products, are naturally low on the glycemic index. Weight-loss diets based on the glycemic index typically restrict foods with a relatively high glycemic index ranking, such as potatoes and corn. However, there also are health benefits from these foods, so you don't necessarily have to eliminate them from your diet.

Feb. 08, 2011 See more In-depth