The Importance of Carbohydrates: Functions & Impact of Deficiency

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  • 0:01 Carbohydrates
  • 0:33 Functions of Carbohydrates
  • 3:07 Deficiency of Carbohydrates
  • 3:55 Lesson Summary
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Lesson Transcript
Instructor: Rebecca Gillaspy

Dr. Gillaspy has taught health science at University of Phoenix and Ashford University and has a degree from Palmer College of Chiropractic.

The main function of carbohydrates is to provide the body and brain with energy. An adequate intake of carbs also spares proteins and helps with fat metabolism. Learn about the roles carbohydrates play and what happens when you don't get enough of them.


Just like your car needs fuel to make it run, your body needs fuel to make it go. Of course, your body doesn't run on gasoline - it runs on carbohydrates. Carbohydrates, found in foods like grains, fruits, beans, milk products and vegetables, are by far your body's favorite source of energy, yet providing your body with pep is not the only role carbs play. In this lesson, we will take a look at the functions of carbohydrates as well as what happens when you don't get enough carbs in your diet.

Functions of Carbohydrates

After you enjoy a meal, the carbohydrates from the foods you consumed are broken down into smaller units of sugar. These small units get absorbed out of your digestive tract and into your bloodstream. This blood sugar, or blood glucose, is transported through your bloodstream to supply energy to your muscles and other tissues. This is an important process; in fact, we could say that of the different functions of carbohydrates, supplying energy to the body is the main role.

Most of your body cells use the simple carbohydrate glucose for energy, but your brain is particularly in need of glucose as an energy source. So, we can add that an important function of carbs is supplying energy to the brain. If you have ever gone on a low-carb diet and felt like your brain was foggy for a few days, then you experienced just how important carbohydrates are to proper brain function.

Another function of carbohydrates is to prevent the breakdown of proteins for energy. By consuming sufficient amounts of carbohydrates in your diet, you ensure that your body can meet its energy needs, but if your intake of carbs is too low, or you are using them up too quickly, such as during intense exercise, then your body is forced to break down proteins for energy.

Protein is kind of like the backup generator when the primary energy source goes out. It's great that the body has this backup system in place, yet when proteins are used up for energy, they are no longer available to do their life-sustaining jobs, like helping with muscle contractions and maintaining muscle and other body tissues.

Carbohydrates also help with fat metabolism. If the body has enough energy for its immediate needs, it stores extra energy as fat.

To access this stored energy, your body needs the working energy of carbohydrates. If your diet is deficient in carbohydrates, like if you're trying a crash diet or a strict low-carb diet, then fat metabolism cannot proceed normally, and the result is the formation of ketones. Ketones are acidic molecules formed by partially broken-down fats. Ketones can be used by your body for energy, and they can even spare some protein from being broken down, but if too many ketones are present in the blood they lead to a condition called ketosis. This makes the blood acidic, which can hinder normal body processes; a person in ketosis will also have some noticeable symptoms, including headaches, a dry mouth and an odd, fruity smell to their breath.

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