3 Functions of Carbohydrates and Why They're So Important

The body mainly uses carbohydrates as a source of energy.
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There are many essential nutrients the human body requires to function properly, and carbohydrates are at the top of the list.


With all the fuss around low-carb diets, you may think carbs aren't that important after all. There are different types of carbs, which is why foods like potatoes are associated with having more nutrients than cookies, and they're critical for human functioning.

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Here's how carbohydrates help your cells do their jobs.

The Functions of Carbohydrates

1. Carbs Produce Energy

The main function of carbohydrates revolves around energy production. This is why many athletes follow carb-heavy diets that include foods like sweet potatoes, bananas and dried fruits.


"In human cells, the role of carbohydrates is to provide energy," explains registered dietitian Christine Byrne, MPH, RD, LDN. "The process of breaking down — also called metabolizing — carbohydrates creates energy for our cells."

The body converts carbohydrates into glucose (sugar), which is the body's main form of energy. Most cells use glucose, and it's especially important for the brain.


When you think of using energy, you may think of going for a hike or spending an afternoon doing chores. But you expend energy doing even the smallest tasks including basic human functions, like breathing, contracting your muscles and maintaining your body temperature, according to Oklahoma State University.

2. Carbs Help With Energy Storage

Like taking leftovers from a restaurant, your body stores excess energy for later.


When carbohydrates you eat are converted into energy for cells to use, the result is glucose, according to the Cleveland Clinic. Sometimes, there's more glucose available than the body needs at the moment, but it doesn't go to waste.

"In order to be used as energy, all types of carbohydrates are eventually broken down and converted into glucose by our bodies. Some of that glucose is used for energy immediately, and the rest of it is stored in our liver and various other tissues as glycogen," Byrne says.



Glycogen is used when you need a quick burst of energy or when the body hasn't gotten enough glucose from food, according to Nemours Children's Health. It's also important for regulating blood sugar levels.

3. Carbs Spare Protein From Being Broken Down

Eating enough carbs ensures that there's enough glucose or glycogen available in the body as energy sources to use immediately or tap into later.


If glucose and glycogen are unavailable, some cells can break down fat for energy. However, other cells, such as brain, nerve and developing blood cells, can't use fat and must turn to protein. Breaking down protein for energy can lead to muscle loss, according to Oklahoma State University.

To prevent this, make sure you eat enough carbohydrates. Carbs have a protein-sparing function, protecting muscle tissues. You need your muscles to survive and help protect your joints.


Protein helps build your muscles, but you don't want to rely on just protein for energy — that's carbohydrates' function.

Types of Carbohydrates

In simple terms, the two main types of carbohydrates include simple and complex carbs.

There's room for both in your diet, but complex carbohydrates tend to be richer sources of nutrients. Simple carbs can also have negative health effects, such as causing blood sugar to rise quickly, according to Harvard T.H. Chan School of Public Health.


On a molecular level, there are three main types of carbohydrates:

  • Monosaccharides:​ Monosaccharides are the simplest form of carbohydrates. They're known as simple sugars. "Mono" means one, so they are one unit of sugar. Examples include glucose, fructose and galactose.
  • Disaccharides:​ Disaccharides consist of a pair of monosaccharides — "di" means two. These include sucrose, lactose and maltose.
  • Polysaccharides:Polysaccharides are long chains of monosaccharides. They're often called "complex carbs," and they include starch, cellulose and glycogen.

While all provide energy for cells, complex carbohydrates also provide the most vitamins, minerals and fiber. You need roughly 225 to 325 grams of carbs per day, according to the Mayo Clinic. Opt for sources including fruits, vegetables, grains and legumes (beans, lentils and peas).




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