Are Carbs Bad for You? Everything You Need to Know for a Healthy Diet

Learn how to choose the right carbs and how this macronutrient can have major health benefits to help you reach your goals.

different-type-of-carbs-as-breads
by
Kelsey Kunik, RDN
— Signos
RDN
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Updated by

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Science-based and reviewed

Published:
February 29, 2024
January 18, 2024
— Updated:

Table of Contents

It’s a common myth (and fear) that carbs are bad for you and will ultimately lead to weight gain and a slew of other health problems. While it’s true that carbohydrates cause blood sugar levels to rise, and too many of the wrong carbs could lead to weight gain, they also have plenty of health benefits and give your body much-needed energy. 

We’re busting this diet myth by reviewing the types of carbohydrates you can eat, the many health benefits they offer, and what determines how many carbs you need. By the end of this article, you’ll feel confident eating the right carbohydrates to support your health and wellness goals.

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What Are Carbs?

Carbohydrates are one of three macronutrients (in addition to protein and fat) that support essential processes in your body in addition to providing four calories of energy per gram. When you eat carbohydrates, your body breaks larger sugar and starch structures down into glucose, which then enters the bloodstream, travels to your cells, and gives your body energy. 

Fiber is also a type of carbohydrate that is processed a little differently, staying mostly intact without the same increase in blood sugar. 

Carbohydrates can be found in plant foods, including fruit, vegetables, grains, seeds, nuts, legumes, and foods that have natural sugar, like milk. Some foods, like candies, cookies, cakes, pastries, and some sauces and condiments, have sugars added to them, increasing the amount of carbohydrates found in them. 

Types of Carbohydrates

a mashup of sweet carbs

Not all carbohydrates are processed and used by the body in the same way. You may have heard that some carbs are “good carbs” while others are “bad carbs.” Applying these titles is a bit of an oversimplification, but it’s true that some types of carbohydrates are health-promoting, while you’d benefit from limiting other types in your diet. 

Here are the three main types of carbohydrates and where you’ll find them:

  • Sugars: This is the simplest type of carbohydrate, typically made up of two types of sugar molecules bonded together. You’ll find sugars in fruit and vegetables (fructose), dairy products (lactose), and table sugar (sucrose). Honey and maple syrup, which people often use as a natural sweetener, are also considered sugar. 
  • Starches: You’ll hear these referred to as complex carbohydrates. They’re made up of long chains of simple sugars that take more time and effort to break down. The slower digestion leads to a slower release of sugar into the bloodstream and more stable energy. Grains like wheat, rice, and quinoa, bread, pasta, cereals, and vegetables, including corn, peas, potatoes, beans, and winter squashes, are all high in starch. 
  • Fiber: This type of complex carbohydrate can’t be broken down and digested. Fiber is important because it slows down the digestion of the other nutrients in your meal, helps you feel full, and has other benefits like reducing constipation and lowering blood sugar levels and blood cholesterol levels.1 Fiber is found in many grains, nuts, seeds, lentils, vegetables, fruit, and beans. 

Benefits of Carbs

Although carbs may have a bad reputation, they offer more health benefits than detriments, especially if you’re choosing complex carbohydrates and fiber over simple sugars. Here are just some of the benefits of eating healthy carbohydrate foods. 

Carbs Give You Energy

Carbohydrates provide four calories of energy per gram that’s used as fuel by your brain, heart, and other organs and body systems. When you eat carbohydrates, whether simple sugars or starches, they’re broken down into glucose, which travels through your blood to your cells and fuels a wide variety of body processes essential for living. 

Carbs Are Your Brain’s Favorite Fuel

While your brain can use other fuel sources if needed, carbohydrates are its favorite. When resting, your brain is using 20 to 25 percent of the glucose in your body.2 A well-fueled brain is important for focus, short and long-term memory, and learning new skills and information, but the type of carbohydrates you eat matters.

A balanced diet that includes complex carbohydrates is related to successful brain aging and better short and long-term memory, whereas a diet high in simple carbs can have a negative effect on attention, memory, verbal skills, and more.3

Carbs Support Muscle Recovery

If you’re working on your fitness through aerobic exercise or strength training, eating a diet that includes complex carbohydrates can help you preserve and increase lean muscle. A July 2023 review found that low-carb diets inhibited muscle growth and performance while training.4 After just 24 hours on a low-carbohydrate diet, signs of using protein as a source of energy (instead of muscle building and other important body processes) can begin to occur. 

Carbs Promote Heart Health

Fiber can be broken down into two different types that each have a significant effect on health. Soluble fiber is found in foods like fruit, vegetables, oats, and barley and can improve your heart health by helping to lower cholesterol levels in the blood and reduce blood pressure in people with hypertension. 

As you eat foods that include soluble fiber, your digestion slows, and the fiber absorbs fat from the food you eat before it can be packaged into artery-clogging cholesterol particles. Every 5-gram increase in soluble fiber could decrease LDL-cholesterol (the bad kind) in the blood by an average of 5.57 mg/dL.6

Eating more fiber could also help lower your blood pressure. An April 2022 review found that increasing dietary fiber decreased systolic pressure by an average of 4.3 mmHg and diastolic blood pressure by an average of 3.1 mmHg.7

Carbs Support a Healthy Digestive System

The other type of fiber, insoluble fiber, plays an important role in keeping your digestive system happy. Examples of carbohydrates high in insoluble fiber include whole grains, bran, corn, nuts, leafy greens, and beans. 

These foods increase the speed of digestion and act as a broom, sweeping waste along through your colon. Insoluble fiber helps with more frequent and easier bowel movements and helps protect against colorectal cancer.8

<p class="pro-tip"><strong>Learn More: </strong><a href="give-me-back-my-carbs-with-resistant-starch">Give Me Back My Carbs...with Resistant Starch?!</a>.</p>

How Many Carbohydrates Do You Need?

woman eating while scrolling in coffee shop.

Unfortunately, there isn’t a universal answer for this. The Dietary Guidelines recommend that 45 to 65 percent of your calories come from carbohydrates, with most of that from whole food, complex carb choices.9 But even with this recommendation, your unique carb needs may be different. 

Age, gender, medical conditions, medications, activity level, weight loss goals, and more all determine how many carbs per day a person needs. 

To understand how many carbohydrates you should eat, if you should focus on total carbs or net carbs, or what types of carbohydrates are best for you, we recommend consulting with a doctor and dietitian. This is especially important if you have diabetes and are relying on carb counting or taking glucose-lowering medication. 

How to Choose Your Carbs Wisely?

Choosing foods that are higher in complex carbohydrates and fiber helps you reap all the benefits of carbs without risking the negative effects. Fill up on vegetables, fruit, beans, legumes, nuts, and seeds, and become more conscious of your grain choices. Swap white bread, pasta, and other refined grains for whole-grain options. 

When it comes to sugars, naturally occurring sugars in foods like fruit or milk are paired with other important nutrients like vitamins, minerals, protein, fat, and fiber. Added sugars, however, are a different story. 

The dietary guidelines recommend limiting intake of added sugars to no more than 10% of your daily calories, as these sugars are void of any added nutrition and are associated with an increased risk of heart disease, weight gain, type 2 diabetes, non-alcoholic fatty liver disease, and some cancers.10

If you’re unsure of what carbohydrates to choose or how to make effective changes in your diet, talk with your doctor and dietitian, who can offer specific guidance. 

Learn More About Healthy Nutrition With Signos’ Expert Advice

Are carbs bad for you? Hopefully, you can now confidently answer “no” to this question and feel confident that eating carbohydrates, especially those from whole foods, is good for your health. Keep reading Signos’ blog for more healthy habit support and nutrition information and take our quick quiz to find out if Signos is a good fit for you and your health and wellness goals!

<p class="pro-tip"><strong>Also Read: </strong><a href="how-many-carbs-should-type-2-diabetic-eat-daily">Carb Counting: How Many Carbs Can a Diabetic Have Daily?</a>.</p>

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References

  1. McKeown, N. M., Fahey Jr, G. C., Slavin, J., & van der Kamp, J.-W. (2022). Fibre intake for optimal health: How can healthcare professionals support people to reach dietary recommendations? BMJ, 378, e054370. Retrieved from https://pubmed.ncbi.nlm.nih.gov/35858693/
  2. Goyal, M. S., & Raichle, M. E. (2018). Glucose requirements of the developing human brain. Journal of Pediatric Gastroenterology and Nutrition, 66(Suppl 3), S46–S49. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5959031/
  3. Muth, A.-K., & Park, S. Q. (2021). The impact of dietary macronutrient intake on cognitive function and the brain. Clinical Nutrition, 40(6), 3999-4010. Retrieved from https://pubmed.ncbi.nlm.nih.gov/34139473/ 
  4. Margolis, L. M., & Pasiakos, S. M. (2023). Low carbohydrate availability impairs hypertrophy and anaerobic performance. Current Opinion in Clinical Nutrition and Metabolic Care, 26(4), 347-352. Retrieved from https://pubmed.ncbi.nlm.nih.gov/37057671/ 
  5. Soliman, G. A. (2019). Dietary Fiber, Atherosclerosis, and Cardiovascular Disease. Nutrients, 11(5), 1155.  Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6566984/
  6. Ghavami, A., Ziaei, R., Talebi, S., Barghchi, H., Nattagh-Eshtivani, E., Moradi, S., Rahbarinejad, P., Mohammadi, H., Ghasemi-Tehrani, H., Marx, W., & Askari, G. (2023). Soluble Fiber Supplementation and Serum Lipid Profile: A Systematic Review and Dose-Response Meta-Analysis of Randomized Controlled Trials. Advances in Nutrition, 14(3), 465-474. Retrieved from https://pubmed.ncbi.nlm.nih.gov/36796439/
  7. Akerman, A., Kumar, S., Pham, H. T. D., Coffey, S., & Mann, J. (2022). Dietary fibre in hypertension and cardiovascular disease management: systematic review and meta-analyses. BMC Medicine, 20(1), Article 139. Retrieved from https://bmcmedicine.biomedcentral.com/articles/10.1186/s12916-022-02328-x 
  8. Arayici, M. E., Mert-Ozupek, N., Yalcin, F., Basbinar, Y., & Ellidokuz, H. (2022). Soluble and Insoluble Dietary Fiber Consumption and Colorectal Cancer Risk: A Systematic Review and Meta-Analysis. Nutrition and Cancer, 74(7), 2412-2425. Retrieved from https://pubmed.ncbi.nlm.nih.gov/34854791/
  9. U.S. Department of Agriculture and U.S. Department of Health and Human Services. (2020). Dietary Guidelines for Americans, 2020-2025. 9th Edition. Retrieved from https://www.dietaryguidelines.gov/sites/default/files/2020-12/Dietary_Guidelines_for_Americans_2020-2025.pdf
  10. Paglia, L. (2019). The sweet danger of added sugars. European Journal of Paediatric Dentistry, 20(2), 89. Retrieved from https://pubmed.ncbi.nlm.nih.gov/31246081/

About the author

Kelsey Kunik is a registered dietitian, health and wellness writer, and nutrition consultant

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Please note: The Signos team is committed to sharing insightful and actionable health articles that are backed by scientific research, supported by expert reviews, and vetted by experienced health editors. The Signos blog is not intended to diagnose, treat, cure or prevent any disease. If you have or suspect you have a medical problem, promptly contact your professional healthcare provider. Read more about our editorial process and content philosophy here.

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