Simple Carbs vs. Complex Carbs: What’s the Difference?By Carole Anderson Lucia Reviewed by Briana Rodriquez, R.D. Science-Backed
Carbohydrates often get a bad rap when it comes to weight loss, but understanding the differences between simple and complex carbs is key. Compared to the keto diet, which can call for severe carbohydrate restriction, there are healthy ways to enjoy your favorite foods — even if you’re following a low-carb diet. Carbohydrates are not only an important part of a healthy, well-balanced diet, but when eaten in the right amounts and in the right form, they may actually help your weight loss efforts!
Read on for our complete guide to carbohydrates, which includes information about why they’re important; a discussion of simple vs. complex carbs and which ones can support health and weight loss; and a list of healthy carbs to include in your daily diet (and ones you may want to avoid).
Why carbohydrates are important
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Carbohydrates are one of the three macronutrients (along with protein and fat) that play a crucial role in your body’s healthy functioning.
According to the U.S. National Library of Medicine at the National Institutes of Health,1 carbs are your body’s most important source of energy, as they’re used to produce glucose (blood sugar), which provides the energy necessary for a wide range of functions, from temperature regulation and muscle contraction to red blood cell production and brain functioning. In fact, while other organs can also use both fat and protein as an energy source, your brain and red blood cells prefer glucose for energy.2
What’s more, avoiding carbohydrates completely can actually be harmful to your health, the Physicians Committee for Responsible Medicine3 reports, as doing so may increase the risk of heart disease.
What are the different types of carbohydrates?
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There are two main types of carbohydrates: simple and complex. Simple carbohydrates include sugar, which can be naturally-occurring, but is usually added to most processed foods (as in table sugar, high fructose corn syrup and other sweeteners).4 Complex carbohydrates are found in foods such as beans, fruits, peas, vegetables and whole-grain foods.5
It’s important to note that while fruits and vegetables do contain some simple carbs, they also boast healthy micronutrients and fiber, as well as complex carbs.
Simple vs. complex carbs: What's better?
While both simple and complex carbohydrates are converted to glucose to be used for energy, simple carbohydrates cause your blood glucose levels to rise more quickly than complex carbohydrates do; they also are digested more quickly and tend to be less filling. In addition, they are also digested quicker and tend to be less filling.
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According to the University of Michigan Health System,2 simple carbohydrates in the form of added sugars are the least-healthy type because they cause insulin (which is released in conjunction with glucose to help it enter the cells of your body) to rise too quickly. This rapid rise of insulin causes blood glucose to then drop very quickly, which can leave you feeling hungry and prone to overeating, potentially leading to weight gain. If this pattern continues and you develop consistently high levels of insulin, you may become insulin resistant — which can lead to other serious health conditions, such as Type 2 diabetes.
Complex-carbohydrate foods, on the other hand, are not only digested more slowly, but are also often higher in fiber than simple carbohydrates and potentially help to lower your risk of cardiovascular disease. The fiber in complex carbs may also help prevent obesity and Type 2 diabetes, the Mayo Clinic reports, and it’s vital for your digestive health.6
Research has also shown that a diet rich in complex carbohydrates can lead to reduced body weight and body fat while improving insulin function in overweight people. In fact, the authors of a 2018 study say that healthy carbohydrates in the form of beans, fruit, vegetables and whole grains are “the healthiest fuel for our bodies.”7-8
Now here’s the important point: Since eating foods that contain carbohydrates will cause a release of glucose and insulin, many people assume that carbs are not healthy and can lead to diabetes and other health problems, such as weight gain or obesity. But remember: The type of carbs you eat plays a role. If you eat mostly refined (simple) carbohydrates, you are likely to release greater amounts of insulin, which can lead to health problems down the road. Complex carbs, on the other hand, have been shown to confer a number of health benefits and may even help you lose weight since they contain dietary fiber, which can help you feel satisfied and full for longer.
Healthy carbs vs. unhealthy carbs
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- All non-starchy vegetables, including artichokes, asparagus, broccoli, carrots, cauliflower, tomatoes — the list is nearly endless!
- Beans and legumes, including black, garbanzo, kidney, pinto and white beans; edamame; lentils; and black-eyed, green and split peas
- Fruit — strawberries, blueberries, apples, watermelon, grapes — the list goes on. Just make sure to keep an eye on how much fruit you’re eating if your goals include weight loss.
- Nuts (again, try to watch how many you eat, as they are calorie-dense)
- Starchy vegetables such as corn and potatoes — monitor your portion sizes if you’re trying to lose weight.
- Whole grains, including barley, brown or wild rice, oats, quinoa, whole-wheat bread and whole-grain pasta.
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- Added sugars, including agave nectar, corn sweetener, high fructose corn syrup and ingredients ending in –ose (dextrose, fructose, glucose, maltose, sucrose, etc.)
- Canned fruit in syrup
- Highly processed refined foods, such as cookies and crackers
- Ice cream and similar dairy desserts
- Pastries and other sugary sweets
- Sweetened beverages, such as soda and fruit juice
- Table sugar
- White bread, white pasta and white rice
While groundbreaking research11-15 suggests that some people are inherently able to process carbohydrates more efficiently than others, the fact remains that a certain amount of this nutrient is not only healthy, but also necessary for your body to function normally. We hope we’ve given you the information you need to help you select the healthiest, most nutritious carbohydrates to help fuel your body — and your life!
Did you know your DNA can influence how your body processes carbs? Learn more about Jenny Craig’s DNA Decoder Plan — and find out how following a plan tailored to your unique DNA, including your carb utilization profile, could help your weight loss efforts!
Carole is an award-winning journalist based in Southern California who specializes in health and wellness topics. Her work has appeared in Parents, Fit Pregnancy, Mom & Baby, Yahoo News, Viv magazine and Lifescript. She's won several national awards for her work including a National Science Award and two National Health Information awards. A frequent contributor to Jenny Craig’s Blog, Healthy Habits, she enjoys gardening, spending time at the beach and adopting far too many rescue animals in her spare time.
Favorite healthy snack: jicama dipped in homemade hummus
Briana is a Registered Dietitian Nutritionist and Certified Personal Trainer for Jenny Craig, based in Carlsbad, California. She is passionate about utilizing food as functional and preventative medicine. Guided by a simplistic and optimistic approach, Briana’s philosophy is to help people improve their health and achieve their goals through the development of sustainable habits to live a healthy life. In her free time, you can find her strength training, indoor cycling, coffee tasting, and at local eateries with her husband and two dogs.
Favorite healthy snack: peanut butter with celery alongside a grapefruit-flavored sparkling water (so refreshing!)
This article is based on scientific research and/or other scientific articles and was written by an experienced health and lifestyle contributor and fact-checked by Briana Rodriquez, RDN, Registered Dietitian Nutritionist at Jenny Craig.
Our goal at Jenny Craig is to provide the most up-to-date and objective information on health-related topics, so our readers can make informed decisions based on factual content. All articles undergo an extensive review process, and depending on topic, are reviewed by a Registered Dietitian Nutritionist (RDN) or Nutritionist, to ensure accuracy.
This article contains trusted sources including scientific, peer-reviewed papers. All references are hyperlinked at the end of the article to take readers directly to the source.