Carbohydrates (Digestible)

Carbohydrates (Carbs) can be categorized into digestible and non-digestible carbohydrates. Many non-digestible carbohydrates are fibers, which will be described in the “fiber” section. Digestible carbohydrates include simple sugars (monosaccharides: e.g., glucose, fructose, and galactose; disaccharides: sucrose, lactose, maltose, and isomaltulose) and complex carbohydrates (e.g., starch and glycogen).1 Fruits, fruit juices, dried fruits, sugar sweetened beverages, and sweet desserts and snack foods are major sources of simple sugars. Grains, grain products, potatoes, corn, and vegetables are natural sources of complex Carbs.1 Complex Carbs and disaccharides are digested into monosaccharides in the gastrointestinal tract before absorption. Carbs provide energy (4 kcal/g Carb).2 The 100% Daily Value (DV) for Carbs is 300 g/day (based on a 2,000 kcal diet), among which simple sugars should not exceed 75 g/day.3 Effective as of January 1st, 2020, however, the 100% DV for total carb will be 275 g/day (based on a 2,000 kcal diet), among which added sugar should not exceed 50 g, which is newly defined 100% DV for added sugar.18


  • Brown Rice Syrup (Organic): Organic brown rice syrup is a natural sweetener produced by steeping brown rice with natural enzyme preparations, which convert the mashed grain into a smooth flavored and pleasantly sweet liquid extract and then filtered and concentrated into syrup.
  • Brown Sugar: A distinctive brown color in the brown sugar is because of residual molasses as brown sugar is unrefined or partially refined. Brown sugar is naturally moist and thus soft due to the hygroscopic nature of the molasses.
  • Cane Sugar, Dried Cane Syrup: Cane sugar or dried cane syrup is a natural sweetener produced by sugarcane, which is crushed to collect its juice. After the impurities are removed from the juice, the juice is boiled. By cooling and stirring the sediments, sugar crystals or dried cane syrup are produced.
  • Dextrose: Dextrose, also called glucose, is a natural, simple carbohydrate (monosaccharide) with sweetness made from the hydrolysis of starch in corn (Zea mays).
  • Fructose: Fructose is a natural, simple carbohydrate (monosaccharide) found in many fruits and made commercially by the enzymatic conversion of dextrose (see Dextrose) derived from corn (Zea mays). Also known as fruit sugar, fructose is the sweetest among all naturally occurring sugars and serves as a natural sweetener. Fructose is a low glycemic sweetener, meaning that it does not increase blood sugar as much as glucose or starch after consumption.4-6
  • Honey: Honey is one of the oldest sweeteners and was highly valued by ancient Egyptians for its medicinal and healing properties. It is a nutritious and sweet liquid made from the nectar gathered from flowers by honeybees. It is composed largely of fructose and glucose and also contains water, vitamins, minerals, protein and enzymes. Honey is used as a natural sweetener.
  • Isomaltulose: Isomaltulose is a slowly digested carbohydrate (disaccharide) found as a natural component of honey and sugar cane. It is exclusively made from sugar beets and made into a white crystalline powder. It imparts a sweet taste but is 50% less sweet than sucrose (table sugar). It is a tooth-friendly and low glycemic sweetener, meaning that it does not increase blood sugar as much as glucose or starch after consumption.6-8
  • Maltodextrin: Maltodextrin is a carbohydrate made from the partial hydrolysis (breakdown) of starch present naturally in corn (Zea mays). The partial breakdown produces glucose polymers of varying chain lengths. The solution is filtered, spray-dried, and prepared into a powder. Because the starch is only partially broken down, it has a bland taste and a very low level of sweetness. Maltodextrin serves as a source of carbohydrate in food and nutritional products.
  • Maltose: Crystalline maltose is a simple carbohydrate (disaccharide) made from enzymatic hydrolysis of the starch naturally present in corn (Zea mays). The solution that results is filtered, spray-dried and prepared into a crystalline powder. Less sweet than sucrose, maltose serves as a natural sweetener in many natural products.
  • Molasses: The viscous molasses is produced during the refining process to make sugar from sugarcane or sugar beet. Molasses contains sucrose, glucose, or fructose, and it can be used as syrup alternative. Brown color of the commercial brown sugar is due to molasses.
  • Starch: A large number of glucose units join together to form a polymeric carbohydrate, called starch. There are two types of starch molecules: amylose and amylopectin. Depending on the plant, the contents of amylose and amylopectin vary. There are various kinds of starch: tapioca starch derived from cassava plant (Manihot esculenta), a woody shrub extensively cultivated in South America for its starchy tuberous root; potato starch derived from potato; corn starch derived from corn. There is also glycogen, called animal starch, a starch like glucose polymer stored in animal organs, such as liver and muscle. A starch paste produced by mixing starches with warm water can be used as a thickening agent or gluing agent.

Major Health Benefits

The major role of Carbs is to provide energy to the body.1 Glucose is the most preferred energy source for the brain, especially for infants, and certain cells in the body (e.g., blood cells).1 The remaining glucose can be converted to glycogen and fat for energy storage.1 Carbs also have a protein sparing effect and can prevent ketosis caused by elevated levels of ketone bodies that are produced when fat is broken down to be used as an energy source.1 Glucose can be synthesized from fat and amino acids in the body. Ribose, a five carbon sugar synthesized from glucose in the body, is a component of genetic materials (DNA: deoxyribonucleic acid and RNA: ribonucleic acid) as well as the body’s energy currency, ATP (adenosine triphosphate).9,10 Lactose, a disaccharide, is a major sugar in milk, including human milk.1 Some simple sugars provide sweetness (e.g., fructose, glucose, sucrose, or maltose), among which glucose and maltose raise blood glucose (blood sugar) more rapidly than complex carbohydrates or other simple sugar, such as fructose.1,4,11 Among the sources of complex Carbs, whole grains are healthier than refined grains because whole grain consumption is inversely related to the risk of developing cardiovascular diseases.12 Therefore, it is highly recommended to consume more whole grains (e.g., brown rice) than simple sugars or refined carbohydrates.


Chronic, excessive consumption of simple sugars and refined carbohydrates can increase blood sugar rapidly, which may be implicated in developing type 2 diabetes, obesity, cardiovascular diseases, and dental caries.13-16 Fructose is known to increase blood lipid levels (e.g., triglycerides and LDL cholesterol (bad cholesterol)), and excessive fructose ingestion may cause gastrointestinal intolerance.1,17


  1. National Research Council. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids (Macronutrients). Washington, DC: The National Academies Press, 2005.
  2. Nutrition Facts Label: Total Carbohydrate. U.S. Food and Drug Administration. Accessed in July 2015
  3. US Food and Drug Administration. Guidance for Industry: A Food Labeling Guide (14. Appendix F: Calculate the Percent Daily Value for the Appropriate Nutrients). US Department of Health and Human Services. 2013 January. Accessed in July 2015
  4. Bantle JP. Is fructose the optimal low glycemic index sweetener? Nestle Nutr Workshop Ser Clin Perform Programme. 2006;11:83-91; discussion 92-5. Review. PubMed PMID: 16820733.
  5. Glycemic Index, Nutrition and Healthy Eating, Mayo Clinic. Accessed in July 2015.
  6. Glycemic Index, Food Search, The University of Sydney.  Accessed in July 2015
  7. Holub I, Gostner A, Theis S, Nosek L, Kudlich T, Melcher R, Scheppach W.  Novel findings on the metabolic effects of the low glycaemic carbohydrate isomaltulose  (Palatinose). Br J Nutr. 2010 Jun;103(12):1730-7. doi: 10.1017/S0007114509993874. Epub 2010 Mar 9. PubMed PMID: 20211041; PubMed Central PMCID: PMC2943747.
  8. Food and Drug Administration, HHS. Food labeling: health claims; dietary noncariogenic carbohydrate sweeteners and dental caries. Final rule. Fed Regist. 2008 May 27;73(102):30299-301. PubMed PMID: 18605406.
  1. Murray RF, Harper HW, Granner DK, Mayes PA, Rodwell VW (2006).Harper’s Illustrated Biochemistry. New York: Lange Medical Books/McGraw-Hill. pp. 177-186. ISBN 0-07-146197-3.
  2. Murray RF, Harper HW, Granner DK, Mayes PA, Rodwell VW (2006).Harper’s Illustrated Biochemistry. New York: Lange Medical Books/McGraw-Hill. pp. 294-300. ISBN 0-07-146197-3.
  3. White JS. Straight talk about high-fructose corn syrup: what it is and what it ain’t. Am J Clin Nutr. 2008 Dec;88(6):1716S-1721S. doi:10.3945/ajcn.2008.25825B. Review. PubMed PMID: 19064536.
  4. Seal CJ. Whole grains and CVD risk. Proc Nutr Soc. 2006 Feb;65(1):24-34. Review. PubMed PMID: 16441941.
  5. Mirrahimi A, Chiavaroli L, Srichaikul K, Augustin LS, Sievenpiper JL, Kendall CW, Jenkins DJ. The role of glycemic index and glycemic load in cardiovascular disease and its risk factors: a review of the recent literature. Curr Atheroscler Rep. 2014 Jan;16(1):381. doi: 10.1007/s11883-013-0381-1. Review. PubMed PMID: 24271882.
  6. Mirrahimi A, de Souza RJ, Chiavaroli L, Sievenpiper JL, Beyene J, Hanley AJ, Augustin LS, Kendall CW, Jenkins DJ. Associations of glycemic index and load with coronary heart disease events: a systematic review and meta-analysis of prospective cohorts. J Am Heart Assoc. 2012 Oct;1(5):e000752. doi:10.1161/JAHA.112.000752. Epub 2012 Oct 25. Review. PubMed PMID: 23316283; PubMed Central PMCID: PMC3541617.
  7. Rahelić D, Jenkins A, Bozikov V, Pavić E, Jurić K, Fairgrieve C, Romić D, Kokić S, Vuksan V. Glycemic index in diabetes. Coll Antropol. 2011 Dec;35(4):1363-8. Review. PubMed PMID: 22397288
  8. Augustin LS, Franceschi S, Jenkins DJ, Kendall CW, La Vecchia C. Glycemic index in chronic disease: a review. Eur J Clin Nutr. 2002 Nov;56(11):1049-71. Review. PubMed PMID: 12428171.
  9. Fedewa A, Rao SS. Dietary fructose intolerance, fructan intolerance and FODMAPs. Curr Gastroenterol Rep. 2014 Jan;16(1):370. doi:10.1007/s11894-013-0370-0. Review. PubMed PMID: 24357350; PubMed Central PMCID: PMC3934501.
  10. US Food and Drug Administration. Food Labeling: Revision of the Nutrition and Supplement Facts Labels. US Department of Health and Human Services. Federal Register / Vol. 81, No. 103, p. 33982 / May 27, 2016.