What’s the Difference Between Simple and Complex Carbs? A Dietitian Explains

We’ve all been there — the 3 PM call of the vending machine. You’re feeling the mid-afternoon slump, and even though you brought an apple to work, the candy bar is calling your name. It’s times like this you wonder what’s the difference between simple and complex carbs. Carbohydrates can be confusing, so let’s break down everything you need to know to make smart carb choices that fuel your body, energy levels, and health (1).

Here’s what you need to know about simple vs. complex carbohydrates and practical tips for incorporating the right kinds of carbs into your diet to fuel your lifestyle and health goals. 

What Are Carbohydrates?

Carbohydrates, or carbs, are one of the three macronutrients that provide energy for the body; protein and fat are the other two macronutrients, but we’ll stick with talking about carbs here (1). 

Carbohydrates are found in a wide variety of healthy and less healthy foods (1). 

Examples of healthy carbohydrates include:

• Whole grains
• Fruits
• Vegetables
• Pulses (beans, lentils, peas, chickpeas, soybeans)
• Low- or non-fat, unsweetened dairy (1)

Less nutritious carbohydrates are found in:

• Bagels
• Pretzels
• Ice cream
• Brownies
• Cookies
• Cakes 
• Candy
• Sweetened drinks (2)

Carbohydrates are classified into simple and complex types, depending on their chemical structure (1). Meanwhile, contrary to what you may have heard, carbohydrates aren’t inherently unhealthy (1). In fact, it’s quite the opposite (1). 

“Carbohydrates are a preferred energy source for your brain and are important for supporting energy levels both while at rest and while exercising,” says Stephanie Nelson, RD, MyFitnessPal’s Sr. Lead Nutrition Scientist (1). 

“They break down into glucose and travel from your bloodstream into your cells with the help of insulin, which helps the cells function,” she explains (1).

Carbohydrates have plenty of other benefits, too. To name a few things this macro does:

• Support digestive health
• Help regulate blood sugar levels
• Promote a healthy gut microbiome (1, 3)
• Deliver essential vitamins, minerals, and antioxidants that contribute to overall well-being and protect against chronic diseases (1)

What Active People Should Know About Carbs

Carbohydrates are especially crucial for active people (1). When you eat carbohydrates, they get converted into glucose (sugar) during digestion and then used immediately for energy or stored as glycogen in the liver and muscles for later use (1).

Glycogen stores in muscles serve as a quick source of energy during intense activities, such as running, cycling, and, yes, even weightlifting (4). Without sufficient carbohydrate intake, glycogen stores become depleted, potentially leading to fatigue and reduced performance (4). 

Complex Carbohydrates

Complex carbohydrates are defined by their chemical structure, which consists of long chains of sugar molecules linked together (1). Simple carbs on the other hand are made up of one or two sugar units (1). 

Complex carbs are made of longer chemical chains. This matters for a few key things:

1. Satiation: Those long chains take longer to digest, so complex carbs will keep you fuller longer (1).  

2. Weight loss: The fiber in complex carbs can help with weight loss (5). One study showed that something as simple as eating more fiber was just as effective for weight loss and lowering blood pressure as some more complicated diets (5). 

3. Blood sugar control. Gradual digestion leads to a more stable release of glucose into the bloodstream, producing a slower rise in blood sugar levels (1).

Pro Tip: You can start tracking your fiber intake in MyFitnessPal, aiming to get to 30 grams per day. 

What Are Simple Carbohydrates?

Simple carbohydrates are smaller in their chemical structure and, therefore, easier for the body to break down compared to the long chains found in complex carbohydrates (1). 

Common examples of simple carbs include:

• Glucose (found in grains, potatoes, and rice)
• Fructose (found in fruits)
• Sucrose (which you might also know as table sugar) (1).

Simple carbs can have a more immediate effect on blood sugar and insulin response because they are quickly absorbed into the bloodstream, which may lead to blood sugar spikes (1). 

That said, some simple carbs come packaged with beneficial nutrients like fiber and antioxidants. These better-for-you simple carbs include:

• Fruits 
• Unsweetened low- and non-fat milk
•  Greek yogurt (1)

Meanwhile, it’s a myth that sugary foods give you more energy. These foods are high in added sugars and can leave you feeling more fatigued (7) :

• Candy 
• Soda
• Pastries

For sustained energy, consider focusing on complex carbs (1).

Refined Grains and Processed Foods

Refined grains are grains that have been processed to remove their bran and germ, leaving behind only the starchy endosperm, the starchy middle part of a grain (8). This process changes taste and texture in a way most people like, but it also reduces the grain’s nutrient content (8). 

Common refined grains are what most people think of when they think of carbs:  pillowy white bread, white rice, your typical pasta made from refined flour, crackers, sugary pastries, and many packaged snacks (2). These can often be identified on food labels by terms like enriched flour and wheat flour (without ‘whole’ preceding it) (9). These terms are code for white, refined flour  (9). 

The removal of the bran and germ during refining strips away fiber and many essential nutrients, including B vitamins, iron, magnesium, and antioxidants (8, 9).  

Why Whole Grains Have Benefits

While some refined grains are enriched to replace lost nutrients, they lack the naturally occurring fiber and other beneficial compounds found in whole grains (8). This may be why, over time, whole grain intake is associated with a lower risk of heart disease and better blood sugar management than refined grains (10, 11). Whole grains may also help you reach or maintain a healthy weight (12).

Whole grains retain all three parts of the grain—the bran, germ, and endosperm—making them higher in fiber, vitamins, minerals, and healthy fats (8). To make healthier choices, look for products labeled 100% whole grain or whole wheat as the first ingredient (9).

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About the Experts

Stephanie Tarnacki, RD is a Food Data Curator at MyFitnessPal. She received her Bachelors in Dietetics from University of Northern Colorado and completed her Dietetic Internship at Montana State University.

Samantha Cassetty, MS, RD, is a nationally recognized food and nutrition expert, media personality, nutrition consultant, and author. Cassetty is a former nutrition director for Good Housekeeping and the co-author of the book Sugar Shock.

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Examples of complex carbohydrates 

Complex carbs are found in whole, minimally processed foods that provide fiber, vitamins, and minerals (1). 

Examples include:

• Whole Grains, such as brown rice, quinoa, oats, whole wheat bread, and popcorn (yes, you read that right!) (12).
• Pulses, like lentils, chickpeas, and black beans. Edamame is another complex carb similar to pulses (1). 
• Vegetables, particularly starchy ones, like sweet potatoes and butternut squash. Non-starchy vegetables are much lower in carbohydrates (13).

Examples of simple carbohydrates 

Simple carbs are naturally present in some whole foods but are also added to many processed items (1).  

Examples include:

• Fruits like apples, bananas, and berries (1). 
• Plain, unsweetened milk and yogurt (1). 
• Processed foods with added sugars, such as candy, sugary cereals, pastries, and sodas (1). 
• Maple syrup, honey, and table sugar (1). 

You don’t have to worry about the natural, simple sugars in fruits and dairy foods, but it’s helpful to limit the added sugars in your diet (13). 

That’s because a diet that’s high in added sugars is associated with a higher risk of numerous health problems, such as heart disease, cognitive problems, high blood pressure, type 2 diabetes, weight gain, obesity, liver disease, and kidney disease (14).

When to Limit Simple Carbohydrates

On average, adult men consume 19 teaspoons of added sugar per day, while adult women consume 15 teaspoons (15). That equates to about two cans of soda for men, and 1 ½ cans of soda for women, so it’s easy to see how added sugars add up fast! 

Compare that to the American Heart Association’s recommendations, which advise limiting added sugars to no more than nine teaspoons per day for men and no more than six per day for women (14). This means most people–even if you’re perfectly healthy–will benefit from lowering the added sugar in their diet (14, 15).

There are certain populations who might get even more benefits from reducing added sugar intake. For instance, added sugars have no nutritional value–they only add calories to your diet. So, if you’re trying to lose weight, cutting calories from added sugars may help you achieve the calorie deficit needed for weight loss (14).

Who Needs to Pay Special Attention to Carbs?

If you have diabetes, it’s helpful to control the amount of carbohydrates you eat in one sitting (13). Since complex carbs offer so many nutritional benefits, it’s beneficial to emphasize those and instead focus on lowering the amount of simple carbs with added sugar that you consume (13). Read  3 Things To Know Before Starting a Low-Carb, High-Fat Diet before limiting all carbs in your diet.

Although most people benefit more from lowering their intake of simple carbs (with the exception of meeting fruit and plain dairy recommendations), there are some people who may benefit from including them in their diet. 

If you’re an athlete or participating in very intense, prolonged exercise–say, running a half marathon or going on a six-hour hike, you may need simple carbs to help fuel your workout (4). 

“Carbohydrate consumption pre- and post-workout can support energy levels during activity and recovery post-workout,” explains Nelson (4). Still, focusing on healthier simple carbs, like applesauce and dried fruit, will provide more beneficial nutrients as well as an energy boost (4). Find ideas for pre- and post-workout snacks and refuel ideas here. 

Here’s How to Reduce Added Sugar

Here are some ways you can lower the added sugars in your diet:

• Switch from soda to an unsweetened flavored seltzer or herbal tea (2). 
• Choose plain versions of foods like oatmeal, Greek yogurt, and cereal (2). If this is challenging at first, mix the plain versions with your favorite sweetened versions. This will still lower the overall sugar you’re consuming.
• Have smaller servings of dessert foods or replace them with healthier alternatives that satisfy your sweet cravings. Go to the recipes section of the MyFitnessPal blog (which you can access in your app) for some healthier ideas.

Frequently Asked Questions (FAQs)

The Bottom Line

Carbohydrates are often misunderstood, but they’re your body’s preferred source of energy, and they aren’t inherently unhealthy (1). Understanding the difference between simple and complex carbohydrates is key to knowing which carbs to emphasize for weight loss and overall health (1). 

Your best bet is to focus on complex carbohydrates like whole grains, vegetables, and pulses, which supply fiber and essential vitamins and minerals (2). Fruits and plain dairy are healthy carbs that can help round out your diet (2). Choose simple carbs with added sugars less often, and when you do include them, do so mindfully (2).

The post What’s the Difference Between Simple and Complex Carbs? A Dietitian Explains appeared first on MyFitnessPal Blog.

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2025-02-18 11:22:51