By Mayo Clinic News Network

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 are 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.

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 form 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 a complex carbohydrate, meaning it is made of many sugar units bonded together. Starch occurs naturally in vegetables, grains, and cooked dry beans and peas.
  • Fiber. Fiber also is a complex carbohydrate. Fiber occurs naturally in fruits, vegetables, whole grains, and cooked dry beans and peas.

More carbohydrate terms: Net carbs and glycemic index

Terms such as "low carb" or "net carbs" often appear on product labels, but the Food and Drug Administration doesn't regulate these terms, so there's no standard meaning. Typically net carbs is used to mean the amount of carbohydrates in a product excluding fiber or excluding both fiber and sugar alcohols.

You probably have also heard talk about the glycemic index. The glycemic index classifies carbohydrate-containing foods according to their potential to raise your blood sugar level.

Weight-loss diets based on the glycemic index typically recommend limiting foods that are higher on the glycemic index. Foods with a relatively high glycemic index ranking include potatoes and corn, and less healthy options such as snack foods and desserts that contain refined flours. Many healthy foods, such as whole grains, legumes, vegetables, fruits and low-fat dairy products, are naturally lower on the glycemic index.

How many carbohydrates do you need?

The Dietary Guidelines for Americans recommends that carbohydrates make up 45 to 65 percent of your total daily calories. So, if you get 2,000 calories a day, between 900 and 1,300 calories should be from carbohydrates. That translates to between 225 and 325 grams of carbohydrates a day.

You can find the carbohydrate content of packaged foods on the Nutrition Facts label. The Nutrition Facts label shows total carbohydrates, which includes starches, fiber, sugar alcohols, and naturally occurring and added sugars. It may also list total fiber, soluble fiber and sugar separately. You may also be able to find nutrient calculators online or find information on a manufacturer's website.

Carbohydrates and your health

Despite their bad rap, carbohydrates are vital to your health for a number of reasons.

Providing energy

Your body uses carbohydrates as its main fuel source. Sugars and starches are broken down into simple sugars during digestion. They're then absorbed into your bloodstream, where they're known as blood sugar (blood glucose). From there, the glucose enters your body's cells with the help of insulin. Glucose is used by your body for energy, fueling all of your activities, whether it's going for a jog or simply breathing. Extra glucose is stored in your liver, muscles and other cells for later use or is converted to fat.

Protecting against disease

Some evidence suggests that whole grains and dietary fiber from whole foods help reduce your risk of cardiovascular diseases. Fiber may also protect against obesity and type 2 diabetes. Fiber is also essential for optimal digestive health.

Controlling weight

Evidence shows that eating plenty of fruits, vegetables and whole grains can help you control your weight. Their bulk and fiber content aids weight control by helping you feel full on fewer calories. Contrary to what low-carb diets claim, very few studies show that a diet rich in healthy carbohydrates leads to weight gain or obesity.

Choosing carbohydrates wisely