Key Facts About Carbohydrates
- One medium 5.3 oz potato with skin-on provides 26 grams of carbohydrates, or 9% of the daily value per serving.
- The brain + red blood cells require carbohydrates.
- Consume 130 grams of carbohydrates per day for central nervous system support.
- Choose carbohydrates high in “nutrient density”
- Fruits + vegetables are excellent carbohydrates
Functions of Carbohydrates
The primary function of carbohydrates is to provide energy to the cells of the body, particularly the brain. While most body tissues and organs prefer carbohydrate as their primary fuel source, some, like the brain, red and white blood cells, and certain parts of the kidney require it. 1 Carbohydrates are also an important fuel for the muscles during exercise, particularly intense and/or prolonged exercise, and as such are key to optimal athletic performance. 2
In fact, carbohydrates are so crucial to the body that if you don’t consume adequate amounts in your diet, your body will have to make them—a process known as “gluconeogenesis” (literally translated “to make new glucose”). The most common gluconeogenic substrates are amino acids derived from both dietary sources of protein and body proteins such as muscle and vital organs. 2 Thus, while the body can survive without carbohydrates; it does so at the expense of the body’s protein pool and consequently does not function optimally. 2
Carbohydrate Classification
Carbohydrates can be broadly classified as simple or complex, based on their chemical structure. Simple carbohydrates, as their name implies, have a simple chemical structure consisting of one or two sugar molecules. Examples include the monosaccharides (single sugars)—glucose, fructose, galactose—and the disaccharides (two sugars)—sucrose, lactose, and maltose. Most fruits and dairy products contain an abundance of simple sugars. Soft drinks, ice cream, sweets and pastries also contain significant amounts of simple sugars. 3
Complex carbohydrates, including starch, glycogen, fiber and resistant starch, have a more complex chemical structure, containing two or more sugar molecules linked together. 3 Glycogen is the body’s storage form of glucose, while starch is a plant’s storage form of glucose. Foods rich in starch include grains, cereals and most vegetables, particularly beans, peas, corn and potatoes. 3
Carbohydrate Recommendations
The current RDA for carbohydrates is 130 grams per day based on the amount needed to optimally support the central nervous system (i.e., the brain). 1 If you engage in physical activity, you need more carbohydrate. How much more depends on the intensity and duration of your exercise. 4 The Food and Nutrition Board of the Institute of Medicine (the government body that sets the RDA) has recommended an acceptable macronutrient distribution range (AMDR) for carbohydrates of 45-65% of total daily energy intake. 1
Some people hold the misconception that they need to cut out carbohydrates to manage body weight. But scientific consensus asserts that excess calories are to blame for weight gain, not diet composition. 5 Instead of restricting carbohydrates from your diet, practice common sense when selecting carbohydrate-rich foods—choose nutrient dense whole grains, fruits and vegetables.
References
- Food and Nutrition Board, Institute of Medicine of the National Academies. Dietary Reference Intakes for Energy,Carbohydrate, Fiber, fat, Fatty Acids, Cholesterol, Protein and Amino Acids. Washington, DC. The National Academies Press. 2002; pp 265.
- Burke LM, Hawley JA, Wong SH, Jeukendrup AE. Carbohydrates for training and competition. J Sports Sci. 2011; 29(Suppl 1): S17-27
- Food and Nutrition Board, Institute of Medicine of the National Academies. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, fat, Fatty Acids, Cholesterol, Protein and Amino Acids. Washington, DC. The National Academies Press. 2002; pp 275-276.
- Raatz SK, et al. Resistant starch analysis of commonly consumed potatoes: Content varies by cooking method and service temperature but not by variety. Food Chem. 2016 Oct 1;208:297-300.
- U.S. Department of Health and Human Services and U.S. Department of Agriculture. 2015 – 2020 Dietary Guidelines for Americans. 8th Edition. December 2015. Available at http://health.gov/dietaryguidelines/2015/guidelines/.