Nutrition 101: Carbohydrates
Carbohydrates. Are they good? Are they bad? Do I need them or not? I get these questions a lot, so I decided to create this simplistic guide to give you solid understanding of what carbohydrates are, what they do, and how they should fit in our diets.
What are they?
Carbohydrates are one of the three macronutrients in the diet, meaning one of the three main ingredients in our diets along with proteins and fats. All carbohydrates are composed of a series of carbon, hydrogen, and oxygen molecules. Carbohydrates are divided into subcategories based on the chemical structure. There are 3 types of carbohydrate: starch, sugar, and fiber.
Why do I need them?
Carbohydrate is the main source of energy for the brain, central nervous system, and red blood cells. Carbohydrates are essential – the brain and red blood cells are not able to run efficiently without having enough carbohydrates in the body. Our bodies cannot produce carbohydrate on their own; therefore, we must provide carbohydrates using food sources. When carbohydrate of any kind is eaten, it is converted to the usable form called glucose. Glucose is the scientific term for “blood sugar,” as glucose made from breaking down complex sugars into the most simple and absorbable form. So, when your “blood sugar” rises, this means that there is added glucose in the blood stream from eating foods. This is normal and is the way the body is supposed to function. After carbohydrate is broken down into glucose, the hormone insulin comes into play and helps the glucose get inside of the cells to be used. Insulin allows for the glucose that is floating around the blood stream to be moved out of the blood stream and into the cells- this is what lowers the “blood sugar,” back to what it was before you ate. After glucose has been taken into the cell, it can be transported for use throughout the body (i.e. going to the brain, central nervous system, and cells to do all of the metabolic functions of the body.)
How much do I need?
The U.S. Department of Agriculture Recommended Daily Allowance recommends that the diet be comprised of 45-65% carbohydrate sources for average, healthy Americans. This means that half, or more, of the foods that you eat should be a source of carbohydrate. Of that, half of the carbohydrate eaten in a day should come from whole grain sources. Whole grain products are specifically recommended due to their high fiber content and benefits for digestive and heart health. A simple way ensure that you are meeting your needs is to have carbohydrate at each meal and snack, including a whole grain. The amount of carbohydrates you need every day is individual. This is something that should be discussed with a nutrition professional if you think you would benefit from a more structured recommendation.
What are food sources?
Grains & Grain Products: bread, pasta, rice, oatmeal, barley, couscous, quinoa, grits, tortilla (flour or corn), etc.
Starchy Vegetables: peas, corn, potatoes, sweet potatoes, legumes (beans), lentils
Non-starchy Vegetables: bell peppers, cauliflower, onion, greens, etc. (All vegetables contain some carbohydrate; however, non-starchy vegetables are not a significant source of carbohydrates and should not be used as a carbohydrate source in meals and snacks.)
Baked Goods & Snacks: muffin, cookie, cake, pies, tortes, tarts, crusts, chips, crackers
Fruits & fruit juices
Dairy: milk, yogurt, ice cream
Sugars: table sugar, sugar alcohols (like sorbitol and mannitol), agave, honey, syrup, etc.
Fiber: Fiber is is the indigestible and fermentable part of plants and is naturally-occurring in whole grains, fruits, vegetables, and beans.
What’s a serving?
A serving of carbohydrate is 15 grams; however, using hand measurements is more realistic than counting grams of carbohydrate in most cases. According to the American Heart Association, a serving of dairy, yogurt, fruits, and vegetables is about 1 fist. A serving of grains, grain products, starchy-vegetables, legumes and lentils is about 1 scooped handful. Baked goods and snack products are recommended to be chosen in lesser amounts, as they do not provide as much fiber or as many nutrients as other sources of carbohydrate; however, can absolutely be part of a healthy diet.
Resources:
1. 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 https://health.gov/our-work/food-and-nutrition/2015-2020-dietary-guidelines/
2. Slavin J, Carlson J. Carbohydrates. Adv Nutr. 2014;5(6):760–761. doi:10.3945/an.114.006163
3. U.S. Department of Agriculture. All About the Grains Group. Choosemyplate.gov. https://www.choosemyplate.gov/grains. Nd. Accessed May 30, 2020.