Simple Carbohydrates vs. Complex Carbohydrates

Learn the difference between simple and complex carbs and see examples of each.

oatmeal and fruit

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The two main types of carbohydrates are simple carbs and complex carbs. Simple carbs are found in everything from table sugar 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.

What Is the Difference Between Simple and Complex Carbs?

There are two types of carbohydrates: simple and complex. Simple carbs are short molecule chains. Complex carbs are longer chains.

Carbs, protein, and fat 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 amino acids, 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.

Examples of Carbohydrates

Examples of foods that contain simple carbohydrates include things like fruit, white bread and pasta, and baked desserts. Foods containing complex carbohydrates include whole-grain bread, brown rice, and legumes.

What Are Simple Carbohydrates?

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 lactose (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.

Simple Carb Foods to Avoid

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:

  • Candy
  • Soda
  • Syrups
  • Sugar

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.

What Are Complex Carbohydrates?

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.

Complex Carb Foods to Eat

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

Some examples of nutritious complex carbs include:

  1. Brown rice
  2. Wild rice
  3. Oatmeal
  4. Whole-grain (rather than pearled) barley
  5. Quinoa (a seed)
  6. Buckwheat (a grass)
  7. Starchy veggies like potatoes, sweet potatoes, and corn
  8. Non-starchy veggies like asparagus and zucchini
  9. Lentils
  10. Kidney beans
  11. Chickpeas

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

Limit Refined Foods

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:

  • Bagels
  • Baked goods like cakes and cookies
  • Cereals made from refined grains
  • Crackers
  • Hamburger or hot dog buns
  • Pancakes and waffles
  • Pizza dough
  • Rice snacks
  • Soft sandwich bread 
  • White rice and pasta

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.

Sugars are simple carbohydrates. They're found in candy as well as fruits and milk. Starches and fiber are complex carbohydrates. Starchy foods include bread, cereal, and potatoes, while fiber can be found in fruits, vegetables, and whole grains.

Summary

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.

7 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  2. American Heart Association. Carbohydrates.

  3. Centers for Disease Control and Prevention. Get the facts: Added sugars.

  4. U.S. Department of Agriculture. Dietary guidelines for Americans, 2020-2025.

  5. American Diabetes Association. Get to know carbs.

  6. Ludwig DS, Hu FB, Tappy L, et al. Dietary carbohydrates: role of quality and quantity in chronic diseaseBMJ. 2018;361:k2340. doi: 10.1136/bmj.k2340

  7. National Library of Medicine. MedlinePlus. Carbohydrates.

Additional Reading

By Debra Manzella, RN
Debra Manzella, MS, RN, is a corporate clinical educator at Catholic Health System in New York with extensive experience in diabetes care.