What Are Simple Carbohydrates and Are They Bad For You?

Medically Reviewed By Adrienne Seitz, MS, RD, LDN
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Simple carbohydrates, or “simple carbs”, are a type of sugar present in food. They can occur naturally and artificially in your diet. Simple carbohydrates can cause a sudden rise in blood sugar and insulin levels. Excessive consumption of simple carbs can lead to complications and health conditions. Your body requires three main macronutrients to support health: protein, fat, and carbohydrates.

Carbohydrates are divided into two principal types: simple and complex. They differ based on their chemical structure and how quickly the human body can digest and absorb their sugars.

Simple carbohydrates are sugars that the body digests rapidly, which are then quickly released into the bloodstream. This quick processing and the resulting blood sugar spike can cause tiredness shortly after they are consumed.

This article explains what simple carbohydrates are and how they differ from complex carbohydrates. It also discusses the health effects of simple carbohydrates, examples of simple carbs, which carbs to incorporate into your diet, and recommended intake levels.

What are simple carbohydrates?

A person holds two milkshakes in clear plastic cups.
Lucas Ottone/Stocksy United

Carbohydrates are made up of different types of sugars, starches, and fiber.

Simple carbohydrates are carbohydrates that consist of one or two types of sugars: monosaccharides and disaccharides. They release energy and cause a quick and temporary rise in blood sugar and insulin levels.

Examples of simple carbs include:

  • honey, syrup, and nectar
  • fruit and fruit juice
  • milk and milk products
  • soda and sweetened drinks
  • candy
  • table sugar
  • artificial sweeteners
  • cereals
  • cakes and pastries
  • processed grains such as white flour

Simple vs. complex carbs

Simple carbohydrates have a chemical structure of one or two sugars.

Complex carbohydrates refer to carbs that contain three or more sugars. These sugars are known as oligosaccharides and polysaccharides, and are bonded together in a complex chemical structure.

The body digests complex carbohydrates more slowly than simple carbohydrates, causing a more gradual rise in blood sugar. Complex carbohydrates can make you feel fuller for longer and help manage blood sugar levels after a meal.

Complex carbohydrates also contain fiber and starch. Fiber can aid digestion, and clinicians associate it with a lower risk of certain gastrointestinal diseases.

Examples of foods containing complex carbohydrates include:

  • fruits
  • vegetables
  • unrefined whole grains, such as:
    • rice
    • chickpeas
    • pasta
    • wheat
    • oats
  • seeds
  • potatoes
  • beans

Learn more about carbohydrates including the role of fiber and starch here.

Naturally occurring sugars vs. added sugars

Simple carbohydrates can occur naturally in some foods.

Foods with naturally occurring or unrefined sugars can also contain important nutrients such as vitamins, minerals, and fiber. This means that some of these foods can be beneficial for your health. Examples include:

  • fruits
  • milk and milk products
  • some vegetables

Some of these sugars occur naturally inside plant cells. These plant sugars take longer to digest, meaning blood sugar levels do not spike as quickly.

However, in some cases, manufacturers add these sugars to food in the production process. Some may refer to these as “added” or “refined” sugars.

Manufacturers may add sugars for many reasons, such as to preserve food or to improve the texture, appearance, and taste of food.

However, some foods with added sugars do not have as many nutrients and can have higher levels of sugar than natural sources. This can make them less nutritious and not as beneficial for your health.

Additionally, both natural and artificial sources of simple carbohydrates can be high in “free” sugars. These are sugars that the blood absorbs particularly easily. Examples include:

  • honey
  • plant syrups and nectars
  • fruit and vegetable juices
  • smoothies
  • added sugars, such as in candy, breakfast cereals, and soda

Effects on health

Simple carbohydrates can cause a quick increase in blood sugar levels. This may cause feelings of fatigue, weakness, or thirst.

Including high levels of simple carbohydrates in your diet long term may also contribute to the development of health conditions such as:

When you eat simple carbohydrates, your body responds by instructing your pancreas to make insulin. Insulin is a hormone that allows blood sugar into your cells so that your body can use it for energy.

The more simple carbohydrates you eat, the more insulin your body needs to produce. After a while, your pancreas may not be able to make enough insulin, which can lead to type 2 diabetes.

Alternatively, there may be some benefits to eating simple carbohydrates in moderation.

If you participate in endurance sports such as running or tennis, simple carbohydrates can provide an energy boost before, during, and after your activity. This is why simple carbs are often found in sports drinks and energy bars.

Some people who experience hypoglycemia, or low blood sugar, may also benefit from simple carbohydrates.

Hypoglycemia may be caused by diabetes or medication that affects insulin levels. Consuming simple carbohydrates such as glucose tablets, fruit juice or soda, or plain sugar can help to immediately raise blood sugar levels.

When consumed in moderation, simple carbohydrates can be part of an otherwise balanced diet.

For healthy adults, 45-65% of daily food intake should come from carbohydrates.

However, the Dietary Guidelines for Americans for 2020–2025 suggests that no more than 10% of a person’s daily caloric intake should come from added sugars.

This percentage may also actually be lower for many people, depending on additional factors such as:

  • body size
  • sex assigned at birth
  • health
  • lifestyle factors

Some other factors such as level of alcohol consumption may also affect this number.

The American Heart Association (AHA) recommends limiting added sugars to 6% of your calories per day. For most females in the U.S., this would equal about 100 calories from sugar per day, or around 6 teaspoons. For males, this is about 150 calories or 9 teaspoons daily.

By contrast, according to the Dietary Guidelines for Americans, the U.S. population consumes more than 13% of their calories from added sugars on average.

Contact your doctor or a licensed nutrition professional for advice on your diet and energy intake. They can help design a plan that is appropriate for you.

Carbohydrates to include in your diet

Healthy and nutritious sources of carbohydrates tend to include complex carbohydrates and whole, minimally processed foods. Examples of such carbohydrates include:

  • fruits
  • vegetables
  • beans and legumes
  • grains such as:
    • brown rice
    • whole wheat bread
    • whole grain pasta
    • oats

Carbohydrates to limit in your diet

Carbohydrates to limit in your diet are those that contain added sugars or are naturally high in simple sugars. These can include food sources such as:

  • soda
  • sweets
  • chocolate
  • cookies, cakes, and other sweet bakery items
  • jams
  • table sugar
  • preprepared meals
  • refined or processed grains, such as white bread, pasta, and rice
  • natural sources of free sugars, such as:
    • honey
    • syrups and nectars
    • fruit and vegetable juices
    • smoothies

When enjoyed in moderation, some simple carbohydrates and added sugars can fit into an otherwise nutritious diet.

Learn more about the differences and benefits of brown vs. white rice here.


Below are some frequently asked questions about carbohydrates.

What are the six simple carbohydrates?

Simple carbohydrates consist of one to two types of sugars known as monosaccharides and disaccharides.

These types of sugars include:

  • glucose
  • fructose
  • galactose
  • sucrose
  • lactose
  • maltose
  • ribose

You can spot simple carbohydrates on food labels if the ingredients contain one of these types of sugars.

Which is better for you, simple or complex carbohydrates?

Complex carbohydrates can offer more health and nutritional benefits, as they contain higher amounts of fiber and other nutrients. They also have a more gradual effect on blood glucose levels.

Some foods that contain simple carbohydrates also offer health benefits, such as fruit and milk. However, simple carbohydrates that include added sugars can cause quick blood sugar spikes and provide fewer nutrients. Excessive consumption of added sugars can lead to an increased risk of some diseases.


Simple carbohydrates are carbohydrates that contain one to two types of sugars. The body digests them quickly, rapidly releasing sugars into your bloodstream and causing blood sugar levels to spike. Over time, a high intake of simple carbs may lead to an increased risk of disease.

By contrast, complex carbohydrates have a more gradual effect on blood sugar levels, as the body digests them more slowly.

Some natural sources of simple carbs such as fruit and milk can still be beneficial to your health. Instead of limiting these foods, clinicians recommend limiting sources of simple carbs that include added sugars. These include foods such as candy, soda, and processed foods.

Simple carbohydrates eaten in moderation can fit into a balanced diet. Contact your doctor or a licensed dietitian for advice on what dietary habits may be best for you.

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Medical Reviewer: Adrienne Seitz, MS, RD, LDN
Last Review Date: 2022 Aug 4
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