Nutrition Series: What you need to know about carbohydrates

What are carbohydrates?

Carbohydrates (also called carbs) are a type of macronutrient found in certain foods and drinks.
They are essential food nutrients that your body turns into glucose to give you the energy to function¹.
Carbohydrates consist of carbon and water.  1g=4calories².

Structure of carbohydrates:

• Monosaccharides (simple sugars): glucose, fructose, and galactose.
• Disaccharides (a combination of 2 monosaccharides): Sucrose, maltose, and lactose.
• Oligosaccharides (carbohydrates that contain between 3 and 10 single sugar residues)
• Polysaccharides (up to 3000 glucose units linked together): Starches and fiber.

Types of carbohydrates³

Simple Carbohydrates: One or two sugars (monosaccharides or disaccharides) combined in a simple chemical structure. These easily are utilized for energy, causing a rapid rise in blood sugar and insulin secretion from the pancreas.

• Examples: fructose, lactose, maltose, sucrose, glucose, galactose, ribose
• Foods: candy, carbonated beverages, corn syrup, fruit juice, honey, table sugar

Complex Carbohydrates: Three or more sugars (oligosaccharides or polysaccharides) bonded together in a more complex chemical structure. These take longer to digest and therefore have a more gradual effect on the increase in blood sugar.

• Examples: cellobiose, amylose, cellulose, dextrin
• Foods: apples, broccoli, lentils, spinach, unrefined whole grains, brown rice

Starches: Complex carbohydrates contain a large number of glucose molecules. Plants produce these polysaccharides.

• Examples include potatoes, chickpeas, pasta, and wheat.

Fiber: Non-digestible complex carbohydrates that encourage healthy bacterial growth in the colon and act as a bulking agent, easing defecation. The main components include cellulose, hemicellulose, and pectin.

• Insoluble: Absorbs water in the intestines, thereby softening and bulking stool. Benefits include regularity of bowel movements and a decreased risk of diverticulosis.
  Examples: brans, seeds, vegetables stalks and leaves, brown rice, potato skins.

• Soluble: Helps decrease blood cholesterol and LDL levels, reduces straining with defecation, and blunts postprandial blood glucose levels.    Examples are fleshy fruit, oats, broccoli, and dried beans, psyllium husks, flax seed.

What are total carbohydrates?⁴

Foods and drinks can have three types of carbohydrates: starches, sugars and fiber. The words “total carbohydrates” on a food’s nutrient label refers to a combination of all three types.

More carbohydrate terms: Net carbs, glycemic index and glycemic load⁴

The term “net carbs” often appear on product labels. Typically, the term “net carbs” is used to mean the amount of carbs in a product excluding fiber or excluding both fiber and sugar alcohols.
The glycemic index (GI) classifies carbohydrate-containing foods according to their potential to raise blood sugar levels.
A Glycemic load (GI) value indicates only how rapidly a particular carbohydrate turns into sugar.⁵
Glycemic load=glycemic index x amount of available carbohydrate.¹

Roles of carbohydrate¹

• Used as energy source.
• Are sources of vitamins and minerals.
• Feed good bacteria in intestinal tract
• Aids with regular elimination, removal of toxins

Digestion of carbohydrates⁶

Carbohydrate digestion begins in the mouth where salivary amylase starts the breakdown. After breaking down throughout the digestive system, monosaccharides are absorbed into the bloodstream. As carbohydrates are consumed, the blood sugar levels increase, stimulating the pancreas to secrete insulin. Insulin signals the body’s cells to absorb the glucose for energy or storage. If blood glucose falls, the pancreas makes glucagon, stimulating the liver to release stored glucose.

How many carbohydrates should I eat?³

There is no one-size-fits-all amount of carbohydrates that people should eat. This amount can vary, depending on factors such as your age, sex, health, and whether or not you are trying to lose or gain weight. On average, people should get 45 to 65% of their calories from carbohydrates every day. On the Nutrition Facts labels, the Daily Value for total carbohydrates is 275 g per day. This is based on a 2,000-calorie daily diet. Your Daily Value may be higher or lower depending on your calorie needs and health.

Which types of carbohydrates should I eat?³

You do need to eat some carbohydrates to give your body energy. But it’s important to eat the right kinds of carbohydrates for your health:

• When eating grains, choose mostly whole grains and not refined grains:
  • Whole grains are foods like whole wheat bread, brown rice, whole cornmeal, and oatmeal. They offer lots of nutrients that your body needs, like vitamins, minerals, and fiber. To figure out whether a product has a lot of whole grain, check the ingredients list on the package and see if a whole grain is one of the first few items listed.
  • Refined grains are foods that have had some parts of the grains removed. This also removes some of the nutrients that are good for your health.
• Eat foods with lots of fiber. The Nutrition Facts labels on the back of food packages tells you how much fiber a product has.
  Try to avoid foods that have a lot of added sugar. These foods can have many calories but not much nutrition. Eating too much added sugar raises your blood sugar and can make you gain weight. You can tell if a food or drink has added sugars by looking at the Nutrition Facts label on the back of the food package. It tells you how much total sugar and added sugar is in that food or drink.

Dos and don’ts of carb consumption⁷

Don’t eat carbohydrates alone.

Carbohydrates are the quickest nutrient to be processed in the GI tract and absorbed into the bloodstream. The faster this happens, the higher your glucose spikes and the more stress you induce on your body. The higher the spike, the quicker the crash, leaving you looking for more food very quickly. If you’ve ever consumed a quick bowl of cereal, you know how quickly hunger returns. Carbohydrates by themselves rarely leave you full, at least for long. The more fiber and nutrients the carb contains, the longer you will be satisfied.

Do pair them with health fats and proteins.

Instead of snacking, always think about creating meals, even if it is for a snack. Adding layers of different foods increases protein and fat intake, which increases satiety. If you want an apple, pair it with nut butter or organic cheese. If you want some oatmeal, add in collagen powder or a handful of nuts and seeds. Think layers of different food groups to make it the most nourishing and satisfying meal.

Carbohydrates and blood sugar

Managing blood-sugar levels with diet/ general guidelines¹

1. Eat small meals throughout the day.
2. Eat some protein with every meal and snack.
3. Eat vegetables and fruits.
4. Use healthy fats and oils with every meal.
5. Limit consumption of refined and high glycemic index foods.

Four components of a blood-sugar balancing meal ¹

1. 1/8 of a plate is protein foods.
2. 1/8 of a plate is starch.
3. 3/4 of a plate is non starchy/low GL vegetables.
4. 1Tbs good oil or fat.

Check out part 1 of our nutrition series: Protein in a nutshell
Check out part 3 of our nutrition series: Facts about Fat

References:

1. https://my.clevelandclinic.org/health/articles/15416-carbohydrates ↩︎
2. Nutrition and health: The fundamentals (IHN course notes) ↩︎
3. https://pubmed.ncbi.nlm.nih.gov/29083823/#:~:text=%20Carbohydrates%20play%20an%20important%20role,%20metabolism%2C%20and%20help%20with%20fermentation. ↩︎
4. https://my.clevelandclinic.org/health/articles/15416-carbohydrates ↩︎
5. https://www.sciencedirect.com/topics/medicine-and-dentistry/glycemic-load ↩︎
6. https://www.ncbi.nlm.nih.gov/books/NBK459280/#:~:text=Carbohydrate%20digestion%20beg       ins%20in%20the,the%20pancreas%20to%20secrete%20insulin ↩︎
7. https://thelivingwell.com/the-dos-and-donts-of-carb-consumption/#:~:text=02%3A%20Don’t%20eat%20carbohydrates,you%20induce%20on%20your%20body. ↩︎