You've probably seen ads for low-carb foods and diets, but kids and adults need carbohydrates (say: kar-bo-HI-draytz). Most foods contain carbohydrates, which the body breaks down into simple sugars — the major source of energy for the body.

What Are Carbohydrates?

There are two major types of carbohydrates (or carbs) in foods: simple and complex.

Simple carbohydrates: These are also called simple sugars. They're found in refined sugars, like the white sugar you see in a sugar bowl. If you have a lollipop, you're eating simple carbs. But you'll also find simple sugars in more nutritious foods, such as fruit and milk. It's healthier to get your simple sugars from foods like these. Why? Because sugar isn't added to them and they also contain vitamins, fiber, and important nutrients like calcium. A lollipop has lots of added sugar and doesn't contain important nutrients.

Complex carbohydrates: These are also called starches. Starches include grain products, such as bread, crackers, pasta, and rice. As with simple sugars, some complex carbohydrate foods are better choices than others. Refined (say: ree-FIND) grains, such as white flour and white rice, have been processed, which removes nutrients and fiber. But unrefined grains still contain these vitamins and minerals. They're also rich in fiber, which helps your digestive system work well. Fiber helps you feel full, so you're less likely to overeat. A bowl of oatmeal fills you up better than sugary candy with the same amount of caloriesl.

So which type of carbs should you eat? Both can be part of a healthy diet.

How Does the Body Use Carbs?

When you eat carbs, your body breaks them down into simple sugars, which are absorbed into the bloodstream. As the sugar level rises in your body, the pancreas releases a hormone called insulin. Insulin is needed to move sugar from the blood into the cells, where the sugar can be used as an energy source.

When this process goes fast — as with simple sugars — you're more likely to feel hungry again soon. When it goes more slowly, as with a whole-grain food, you'll be satisfied longer. These types of complex carbs give you energy over a longer period of time.

The carbs in some foods (mostly those with a lot of simple sugars) make the blood sugar level rise more quickly than others. Scientists have been studying whether eating foods that cause big jumps in blood sugar may be related to health problems like diabetes and heart disease.

You're probably already on the right track if you're limiting simple sugars (such as candy) and eating more complex carbs (like vegetables, oatmeal, and whole-grain wheat bread).