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Get excited about nutrition, and learn as you go with these information-packed resources on a wide variety of nutrition-centric topics! Our bistroMD experts review the importance of the macronutrients protein, fat, and carbohydrates, as well as how to make them work most efficiently for you.

Your Essential Guide to Complex Carbohydrates

Individuals generally perceive carbohydrates as a main barrier to weight loss. And although too many carbs (specifically from refined sugar) can result to weight gain, complex carbohydrates (think whole grains) are highly recommended. But what are healthy complex carbs and how can more of them fall into your diet?

Your Essential Guide to Complex Carbohydrates

Carbohydrate 101

Before jumping into your essential guide to complex carbs, it is fundamental to further dissect what a carbohydrate actually is. A carbohydrate is one of the three macronutrients, as fat and protein are the additional two. Each macronutrient is responsible for supplying the body with energy, also known as calories. Carbs are considered to be the body's main source of energy and are quickly utilized by the brain and muscles. Carbohydrates not used for immediate use are stored in the liver or muscles for a later time.

Individuals generally know carbs to be "simple" or "complex." The two forms differentiate relative to their chemical structure and digestion and absorption speed. Simple carbohydrates are generally digested and absorbed more quickly compared to complex carbohydrates. Structurally, simple carbs contain one or two sugar molecules. Simple carbs with one sugar molecule (fructose, glucose, and galactose) are monosaccharides while two sugar molecules (sucrose, maltose, and lactose) are known as disaccharides.

Simple sugars are also recognized as processed and refined sugars. These sugars are found in corn syrups, table sugar, candies, and soft drinks and essentially offer nothing more than sugar and calories. However, not all simple carbs are empty calories stripped away from nutrients and fiber. Simple sugars are also found naturally in nutritious veggies, fruits, and dairy products.

So, What Are Complex Carbs?

Compared to simple carbohydrates (monosaccharides or disaccharides), complex carbohydrates are polysaccharides. Polysaccharides contain three or more sugars and further known as starches. Additionally, complex carbs are generally digested and absorbed more slowly than simple carbs. The gentle absorption helps to keep blood sugar levels sustained and consistent, whereas simple carbs ignite quick energy that may spike those blood sugar levels.

Since complex carbohydrates are generally in their whole, unprocessed form, they tend to be an excellent source of fiber. Additionally, they offer essential vitamins and minerals. Seeking out healthy complex carbs and fiber should not be an obstacle, as these food sources will make discovering them simple:

Whole Grains and Associated Products: wheat, oats, rice, quinoa, millet, rye, barley, farro along with whole-grain breads, cereals, and flours

Beans and Legumes: lentils, soybeans, peanuts, chickpeas, beans including black, kidney, and pinto

Fiber-Rich Fruits: bananas, oranges, raspberries, strawberries, fruits with the skin such as apples and pears

Starchy Vegetables: carrots, potatoes, sweet potatoes, pumpkin, corn, squash, zucchini

Fiber-Rich Vegetables: broccoli, cauliflower, onions, spinach, peppers, tomatoes, and green, leafy veggies such as kale, spinach, and lettuce

When in doubt, added sugar is out! Complex carbohydrates are generally absent of added sugars so when choosing a food product, stray away from added simple sugars. Check the ingredient list and avoid products with raw sugar, brown sugar, corn syrup, and high-fructose corn syrup. As a general complex carb rule, choose plant-based products that promote "whole grains" and divvy away from processed foods.

Christy Zagarella's Photo
Written By Christy Zagarella, MS, RDN. Published on November 07, 2012. Updated on September 20, 2019.


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