All You Need to Know About Carbohydrates: Simple, Complex, Fiber, and What to Choose

Over the years, some diet programs have labeled carbohydrates as "good" or "bad." However, instead of putting a moral label on the foods we eat, it's important to understand how the three macronutrients—fats, protein, and carbohydrates—work together to keep us functioning at our best.

What are Carbs and Why Are They Important?

Carbohydrates (carbs) are an essential energy source and vital for good health. When we eat carbohydrates, our body converts them into glycogen (sugar), supplying the energy we require for bodily functions.

Although there are recognized benefits to reducing refined carbohydrate intakes from ultra-processed foods, most people benefit from keeping natural carbohydrate sources, like fruit, starchy vegetables, beans, and whole grains, in their eating plan. While some carbs are healthier than others, it is all about balance and moderation when creating a healthy diet.

Eliminating all carbohydrates can leave you feeling fatigued, impair exercise performance, and even cause nutrient deficiencies. Carbohydrates can fit into your healthy eating plan so you can enjoy a variety of foods while still making progress towards your fitness goals.

Types of Carbohydrates

Instead of calling carbohydrates "good" or "bad," they can be more accurately described as "complex" and "simple." Both kinds of carbohydrate can also be refined.

Complex Carbohydrates

Complex carbohydrates are defined as polysaccharides, which simply means that they contain at least three glucose molecules. They are found in foods high in fiber and starch, which take longer to digest and contain important vitamins, minerals, prebiotics, and antioxidants.

Slow-release energy helps regulate appetite and blood sugar, keeping you feeling full for longer. Whole grains, beans, quinoa, legumes, oats, and brown rice are excellent sources of complex carbs. 

Simple Carbohydrates

Simple carbohydrates contain only one or two sugar molecules; they are referred to as monosaccharides and disaccharides. Foods high in simple carbs contain naturally occurring or added sugars and are digested quickly.

Fruits, juices, milk, white flour, white rice, sugar, and soda are simple carbs. While some of these foods provide nutrients (like vitamins in fruit and protein in milk), processed carbohydrates like crackers and chips are lacking in essential nutrients, such as fiber and vitamins.

Swapping 'Simple' Carbs for 'Complex' Carbs

Switching out refined carbohydrates for complex carbs gives you more bang for your buck, nutritionally speaking. For instance, eating an ear of corn from the husk versus corn flakes, a peeled orange over orange juice, or a baked potato instead of a bag of potato chips will fuel your body with the fiber and micronutrients required for sustained energy and disease prevention.

Excellent Carb Choices

Here are a few examples of carbohydrates worth adding to your grocery list:

• Beans and legumes: Have them cold or baked into dishes.
• Nuts and seeds: These provide healthy fats in addition to complex carbs.
• Tubers: Sweet potatoes and white potatoes (ideally, with the skin) are a source of complex carbs.
• Vegetables: Eat a variety every day for fiber and vitamins.
• Whole fruits: Keep the skin on when you can to boost fiber intake.
• Whole grains: Oats, quinoa, brown rice, whole grain bread, and barley, and foods made from them (such as bread and pasta) offer complex carbs.

During food processing, many of the nutritious properties of natural foods are stripped away (namely fiber). Sugar, sodium, and preservatives are then often added to enhance flavor and prolong shelf life. Unfortunately, these additives do little to benefit our health.

That's why whole foods are usually a better choice than processed ones. Some foods, such as cereal and bread, do have nutrients added back in, but it's ideal to eat more whole foods instead of relying on these fortified foods.

Limit These Carbs

Here are some examples of processed carbohydrates that should take up limited space in your overall eating plan:

• Juices: Even 100% juice is a concentrated source of sugar; try diluting it with water or limiting it to one glass a day.
• Processed snacks: Pretzels and crackers made from refined flour, sugary granola bars, and candy should be consumed in moderation.
• Sugary drinks: Soda, sports drinks, chocolate milk, and sweetened teas add a significant amount of sugar to your diet.
• White bread: Refined flour products usually lack fiber and vitamins and contain additives that you should eat less often.

Types of Fiber in Carbs

Dietary fiber comes mainly from complex carbohydrates. The Dietary Guidelines for Americans suggest we consume 45% to 65% of our daily intake from these carbohydrates to meet our body's fiber requirements.

Fiber intake should range from 25 to 35 grams daily. Studies show that eating enough fiber helps with body fat and cholesterol reduction, improved digestion, and reduced risk of diabetes and cancer. We require two types of fiber for optimal health: insoluble and soluble.

Insoluble Fiber

Insoluble fiber isn’t broken down during digestion or absorbed into the bloodstream. It adds bulk to stool for easier elimination, reducing the incidence of constipation and protecting against colon cancer.

The following foods are high in insoluble fiber:

• Barley
• Brown rice
• Bulgur or whole-grain cereals
• Couscous
• Fruits
• Most vegetables
• Seeds
• Wheat bran
• Whole wheat bread

Soluble Fiber

Soluble fiber absorbs water and becomes a sticky gel inside our digestive tract that helps soften the stool, making it easier to pass. It also binds to cholesterol and sugar, mitigating their release into the bloodstream.

Soluble fiber acts as a prebiotic, promoting good gut bacteria, reducing inflammation, and boosting immunity. The following foods are great sources of soluble fiber:

• Avocados
• Barley
• Dry beans and peas
• Most fruits
• Nuts and seeds
• Oat bran
• Oatmeal

Effects of Low-Carb Diets

While low-carb diets may be effective for initial weight loss, they might not be the best option for everyone. For example, while low-carb diets can help older and obese adults to lose more weight, more active people often require a larger amount of carbohydrates in the diet for energy.

Research also shows a potential link to increased all-cause mortality with low-carb diets. Additional research shows that low-carb diets might increase the risk of heart complications, including strokes and heart failure.

Low-carbohydrate diets might also adversely affect hormones, including interfering with the menstrual cycle and leading to fatigue and mood disruptions.

What to Look For

The following carbohydrate comparison explains how you can find the best carbs for your health:

Qualities to seek out in carbohydrate foods:

• High fiber content: Compare labels to get enough fiber every day.
• Minimal processing: Look for foods low in refined sugars, refined grains, sodium, and saturated and trans fats.
• Nutrient-rich: Enjoy a variety of nutrients from colorful, natural foods.

Qualities to avoid in carbohydrate foods:

• Highly processed: Long ingredients lists and Nutrition Facts that show high sodium, trans/saturated fats, and sugar
• Nutrient-poor: Low in vitamins, minerals, and fiber
• Refined grains: Instead of "enriched flour," search for food labels with the word "whole"

Studies show that refined sugars, like high fructose corn syrup and white table sugar, make up more than 20% of the calories we eat each day. Refined sugars are linked to disease, obesity, and type 2 diabetes. You can spot added sugars on a food label because they usually end in "-ose."

Frequently Asked Questions

How many carbs a day is healthy?

The 2020-2025 U.S. Dietary Guidelines for Americans recommends at least 130 grams of carbohydrates per day. Put another way, between 45% and 65% of your daily calorie intake should come from carbohydrates.

What are good carbs for someone with diabetes to eat?

The American Diabetes Association recommends that people with diabetes get most of their carbohydrates from whole, unprocessed, non-starchy vegetables, such as asparagus, zucchini, leafy greens, mushrooms, tomatoes, bell peppers, broccoli, green beans, cabbage, and cauliflower. These vegetables contain a lot of fiber and fewer simple sugars, helping to regulate blood sugar levels.

Additionally, people with diabetes can consume some fruit and whole, minimally processed grains, beans, and starchy vegetables such as sweet potatoes, corn, chickpeas, black beans, brown rice, and whole-wheat bread.

A Word From Verywell

Carbohydrates are essential for good nutrition and sustained energy. Choosing unprocessed carbohydrates more often than refined ones will help your body gain the maximum benefits that this macronutrient has to offer. While there are no "good" or "bad" foods, it's wise to consider refined carbs once-in-a-while treats as opposed to a significant portion of your dietary pattern.