The two main types of are simple carbs and complex carbs. Simple carbs are found in everything from table to fruit, while complex carbs, or starches, come from whole grains and vegetables like sweet potatoes.

Both types of carbs give your body energy. Simple carbohydrates provide short bursts of energy. Complex carbohydrates take longer for your body to break down, so they are a longer-lasting energy source.

This article explains how simple and complex carbs work and offers a list of simple carbs to avoid and complex carbohydrates to eat.

There are two types of carbohydrates: simple and complex.

Simple carbs are short molecule chains. Complex carbs are longer chains.

Carbs, , and are the three main nutrient groups in the food we eat. During digestion, all three are broken down into elements the body can use for energy. For example, protein is reduced to , and fat breaks into fatty acids, both of which are stored for future use.

Carbs are different. They are broken down into sugars that, after making a quick stop in the liver, go into the bloodstream and become an immediate source of energy for the body's cells to use. Because they're short molecule chains, simple carbs are easy for your body to break down.

Complex carbs take longer.

As the name suggests, simple carbs have a very basic chemical structure. They may be monosaccharides comprising a single sugar molecule, like glucose. Or they may be disaccharides, which have two simple sugars linked together, as with (milk sugars).

Simple carbs are fairly easy for the body to digest. Enzymes in the small intestine break them down before they enter the bloodstream. Any sugar that isn't used right away is stored as fat, and that's why eating foods with lots of added sugar can add to weight gain.

Many foods contain simple carbs and are rich sources of vitamins, minerals, and other nutrients.

These foods include things like fruit, dairy, and some vegetables.

Not all simple carbs are nutritious. Many simple carbs are found in refined sugars, which add calories but lack vitamins, minerals, and fiber.

Examples of simple carbs to limit or avoid include:

The added sugars in cookies, pastries, and many other processed foods are also simple carbs. But these tend to be "empty calories" with little nutritional value, and they more easily lead to weight gain and health problems like heart disease.

The Centers for Disease Control and Prevention (CDC) recommends limiting added sugars to less than 10% of total daily calories.

For most adults, that comes out to about 12 teaspoons. Kids under 2 shouldn't have any added sugars at all.

Complex carbs are made of longer, more complex chains of sugar molecules. These are called oligosaccharides and polysaccharides. Complex carbs take longer to digest than simple carbs do. This means they have a less immediate impact on blood sugar, causing it to rise more slowly.

Some complex carbs are better choices than others. The healthiest complex carbs have not been processed or refined and include whole grains, and , and beans and legumes.

Some examples of nutritious complex carbs include:

All of these foods are excellent sources of fiber. Fiber helps keep blood sugar levels from spiking too high, helps control levels, and is essential for digestive health.

With complex carbs, it's best to avoid or limit refined grains and processed foods made with them. "Refined" means two of the three elements of each kernel of grain—the bran and the germ—have been removed, along with the fiber, healthy fats, and nutrients found in them.

The part of the kernel that's left is the starchy endosperm. It has less fiber and nutrients, even though vitamins and minerals are sometimes added to refined grains.

Products made with them are sold as "enriched," but there really is no substitute for the natural grains.

Processed foods made with refined grains include:

Many of these foods are also sources of added sugar, making them even less ideal for managing blood glucose. But that doesn't mean you must eliminate everything on the list above. Many of these refined foods also come in whole grain options, which can be a nutritious way to continue enjoying them.

Carbs are necessary for a healthy diet. Simple carbs have a basic chemical structure and are easy for the body to digest. Some simple carbs, like fruit and dairy, are good for you, while others, like candy, soda, and sugar, are unhealthy and should be limited.

Complex carbs have longer, more complex chains of sugar molecules and take longer to digest. The healthiest complex carbs include whole grains, most vegetables, beans, and legumes.