Back to Basics: Carbs

By: Sara Zargham

Carbohydrates have been dubbed the devil of diet culture. At least that seems to be the prevailing opinion in the widely misguided world of diet culture. It is a well-known trope that carbohydrates make you fat or that restricting carb intake is a foolproof way to cut weight. Much of the information that promotes these misnomers fails to provide a more holistic view of the matter. Before cutting or monitoring carb intake (or any intake for that matter) perhaps it is worth learning a little more about the role carbohydrates play in the body and why they are so essential.

What are Carbohydrates? – The science stuff

Carbohydrates, along with proteins, and lipids (fats) are one of the three biological molecules (building blocks) of life found in food. They are used as both an immediate and long-term source of energy (The National Institute of Health, 2020). Carbs are made of ‘chains’ of sugar units. A simple carbohydrate has one to two sugar units whereas a complex carb has a longer chain. The three categories of carbohydrates are sugar, starch, and fiber.

Simple carbohydrates (sugar) can be either monosaccharides or disaccharides. Monosaccharides glucose (blood sugar), fructose (fruit sugar), and galactose (found in milk) contain a single unit (Bird, 2017). Disaccharides are made up of two units and include maltose, sucrose, and lactose (Bird, 2017).

Complex carbohydrates (starch and fiber) can be classified as either oligosaccharide (three to ten units) or polysaccharides (more than 20) (Bird, 2017). Oligosaccharides are found in beans and legumes and also onions, leeks, garlic, and some other plant foods (Dolson, 2019). Polysaccharides are found in starch (which has over 3,000 units of monosaccharides), glycogen (the storage form of carbohydrate), and cellulose (the form of carbohydrates in plants), and fiber (lookout for an in-depth analysis on fiber later) (Bird, 2017). 

How are carbs digested?

Carbohydrates provide four calories per gram. In order to use the energy from carbohydrates, our body has to break them down into glucose (remember, blood sugar!) so that they can enter the bloodstream. Carbohydrate digestion begins in the mouth by salivary amylase, an enzyme found in saliva (Hurtado). When you swallow any food, it moves through the esophagus to the stomach where carbohydrates are further digested into a mixture called chyme (National Institute of Diabetes and Digestive and Kidney Diseases, 2017). The chyme then moves to the small intestine where it is further digested by pancreatic amylase, and other enzymes embedded in the walls of the small intestine (Hurtado). Once they are digested, they are either transported to the liver to be stored as glycogen (the storage form of carbohydrates) or released into the bloodstream as glucose to be used as an immediate source of energy. Weight gain, which gives carbs a bad reputation, occurs when we consistently take in more fuel than our body needs. It is easier, to overeat candy and soda than with potatoes and rice because of the way they are metabolized.

Recommended Daily Intake:

According to the Food and Drug Administration (FDA), the recommended Daily Value for total carbohydrate intake is 275g per day based on a 2,000 calorie daily diet. This number should be adjusted based on your individual daily calorie intake (The National Institute of Health, 2020). Given that carbohydrates come in various forms that will be utilized by your body in different ways, the choice in the type and quality of carbohydrate is more important than the number of grams of carbohydrates. So, how do you decide what is a healthy carbohydrate? (lookout for an article on “healthy” carbohydrates coming soon)

Conclusion – What does all of this mean? 

  • Carbohydrates are an essential source of energy required by the human body. 
  • They come in different varieties and are all eventually broken down into glucose to be utilized for energy or storage depending on the body’s needs. 
  • The daily recommended intake of carbohydrates provided by the FDA fails to account for quality. 

Next time you catch yourself condemning carbs, remember that they are not actually evil. They’re ESSENTIAL! Diets that over-restrict carb intake will not help you achieve a healthy body, nor will they make you feel healthier. Moderation is key!

Reference List:

Bird, R. (2017). KINE 4400 Carb [PowerPoint Slides]. Retrieved from https://collab.its.virginia.edu/portal/site/a70db1a5-eb8f-4294-8c8d-5cd5f770be02/tool/daeafb23-455e-4189-9c34-acc27ce215dd?panel=Main

Dolson. (2019, September 25). The benefits of adding oligosaccharides and prebiotics to your diet. Retrieved August 02, 2020, from https://www.verywellfit.com/oligosaccharides-and-prebiotics-health-benefits-2242223

Hurtado, C. (n.d.). Carbohydrate Digestion and Absorption [PDF]. NASPGHAN Physiology Series.

National Institute of Diabetes and Digestive and Kidney Diseases. (2017, December 01). Your digestive system & how it works. Retrieved August 03, 2020, from https://www.niddk.nih.gov/health-information/digestive-diseases/digestive-system-how-it-works

The National Institute of Health. (2020, July 01). Carbohydrates. Retrieved August 03, 2020, from https://medlineplus.gov/carbohydrates.html

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