All You Need to Know About Carbs

Written by Jennifer Scheinman, MS, RDN

In this month’s Nutrient Profile, we are talking about all things carbs. If you are following a keto or low-carb diet, you are likely already reading food labels and counting your carbohydrate grams. However, you still may have questions about carbs — what exactly are they, and what do they do for the body? And what are those items on the Nutrition Facts label?

Whether you should or should not eat carbs for optimal health is one of the more controversial issues in present-day nutrition. To make this decision for yourself, it is important to fully understand what carbs are and in which foods you can find them. Read on to get all your carb questions answered.

What are carbs?

Carbohydrates are a macronutrient found in many food sources. Sugars, starches, and fiber are all types of carbs, and each has a different impact on your health.

Sugars are sometimes referred to as “simple” or “fast-acting” carbohydrates. Their chemical structure is what makes them simple, and because they can be quickly broken down into glucose, they are called “fast-acting.” You may experience an unhealthy rise in blood sugar after eating them. You’ll find simple carbs in sugar, honey, syrup, and foods and beverages made with these sweeteners. Juice is another simple sugar, and milk and fruit may also be considered part of this list. Except for milk and fruit, these carbs are generally not as healthy as their complex starchy cousins. 

Starches are more complex than sugars, chemically speaking, and therefore take longer for the body to digest. Grains, legumes, and starchy vegetables like potatoes, yams, and winter squash are complex carbs. Within the starches category, some are more nutritious than others, due to their level of processing and fiber content. Refined grains such as white bread, pasta, and rice are low in fiber, making them easier to digest, resulting in similar blood sugar spikes as simple carbs. Often, these processed carbs lack other vital nutrients as well. Unprocessed carbs such as whole grains and starchy veggies will have a better impact on blood sugar and will be richer in nutrients. 

Dietary fiber is a type of carbohydrate; however, it is not broken down by our bodies into glucose. It has several important functions, including promoting healthy digestion, balancing blood sugar, keeping cholesterol in check, and fueling a healthy gut microbiome. You’ll find fiber in beans and legumes, whole grains, nuts, seeds, fruits, and veggies. 

Sugar alcohols are a type of sweet carbohydrate that are lower in calories than sugar. They can be found naturally in some fruits and vegetables or manufactured in a lab. For example, while sorbitol is present in fruits and vegetables, it is commercially manufactured from corn syrup. Likewise, erythritol can be found in pears, melons, and other fruit, yet in food manufacturing, it is made by fermenting corn products. Since our bodies don’t digest sugar alcohols iin the same way as sugar, they are a popular alternative for people with diabetes or those limiting their carbohydrate intake. The downside to sugar alcohols is that they are known to cause digestive distress in some people and can have an unpleasant flavor. If you’re looking for a sugar alternative that isn’t a sugar alcohol, allulose is a natural sweetener that tastes and acts like sugar, but does not impact blood sugar or insulin levels.  

What do carbs do for the body?

Carbohydrates in the form of glucose are the preferred energy source for the cells in our body. If you consume carbs in your diet, they are the main source of energy. The brain requires a lot of energy and uses around 120g  of glucose a day. The body stores glucose in the liver and muscle as glycogen for use when blood sugar starts to get low.

It is not necessary to eat carbs, as our bodies can use protein and fat as a source of energy. That does not mean avoiding carbs is a good idea for everyone. Foods like whole grains, fruits, and veggies come with healthy nutrients that are difficult to get when you don’t eat carbohydrate-rich foods. Fiber, certain vitamins and minerals, and phytonutrients found in plant foods can be insufficient on a low-carb plan, so paying proper attention to your diet is essential when watching your carb intake. 

Decoding the Nutrition Label

Learning how to read the Nutrition Facts label can help you determine how many grams and what type of carbs are in the foods you eat. Here is a breakdown of what the label can show you:

• • Total Carbohydrate – This tells you how many total grams of carbohydrates are in one serving of the food. This includes added sugars, sugar alcohols, and fiber. The Dietary Guidelines for Americans recommend that 45 – 65 % of your calories come from carbs, and the % Daily Value is based on that recommendation, which calculates to about 275 g a day for a 2,000 calorie diet. This number may not suit you and is only meant to be used as a general guide.
  • Dietary Fiber – This is the number of grams of fiber in a serving of the food. The % Daily Value is based on 28 grams of fiber per day.
  • Total Sugars – Representing all the sugar in a serving, this number includes the sugar found naturally in the food and that which the manufacturer adds.
  • Added Sugars – If the manufacturer adds sugar to the product, those grams will be listed here. Honey, maple syrup, sugar, high fructose corn syrup, or any other source of sugar that is not found naturally in the product will be included here.
  • Allulose – Allulose is the primary sweetener in Munk Pack’s keto bars. It is a sweetener found naturally in small amounts in maple syrup, figs, and raisins. Munk Pack’s source is produced from non-bioengineered corn. Allulose has virtually no impact on blood sugar and insulin.
  • Glycerin – Glycerin is made from vegetable fats and is used in foods to help keep them moist. While it has a sweet taste, it is not metabolized by the body like sugar and sugar alcohol are. As a result, it does not impact insulin secretion the same way sugar does. 
  • Sugar Alcohols – mannitol, sorbitol, erythritol, and xylitol are commonly used sugar alcohols you may see on a Nutrition Facts label. If a product is making a claim about its sugar content, it must list the grams of sugar alcohols here. If they are not making any claims, it is optional to list the grams of sugar alcohol. 

Net carbs are not usually listed on the Nutrition Facts panel but people use this calculation as a way to determine which carbs will have an impact on blood sugar. To calculate net carbs, you subtract the fiber, sugar alcohols, allulose and glycerin, when applicable. These ingredients are not converted to glucose in the body so they don’t count toward net carbs. 

The Bottom Line

People choose to eat or avoid carbs for many reasons. Whether you are watching your carbohydrate grams or just want to make wiser decisions regarding the type and amount of carbs you eat, the Nutrition Facts panel is an important tool in guiding your choices. 

 

Resources:

1. Carbohydrates. Medline Plus. Published August 2, 2021. Accessed September 30, 2021. https://medlineplus.gov/carbohydrates.html
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3. Hall H, Perelman D, Breschi A, Limcaoco P, Kellogg R, McLaughlin T, Snyder M. Glucotypes reveal new patterns of glucose dysregulation. PLoS Biol. 2018 Jul 24;16(7):e2005143. doi: 10.1371/journal.pbio.2005143. PMID: 30040822; PMCID: PMC6057684.
4. How to Understand and Use the Nutrition Facts Label. FDA. Published online March 11, 2020. Accessed September 30, 2021. https://www.fda.gov/food/new-nutrition-facts-label/how-understand-and-use-nutrition-facts-label
5. ​​What is Sorbitol? Food Insight. Published April 18, 2019. Accessed October 8, 2021. https://foodinsight.org/what-is-sorbitol/
6. Han J. What is Sorbitol (E420) in Food? Uses, Safety and Side Effects. Accessed October 8, 2021. https://foodadditives.net/sugar-alcohols/sorbitol/
7.  Rzechonek DA, Dobrowolski A, Rymowicz W, Mirończuk AM. Recent advances in biological production of erythritol. Crit Rev Biotechnol. 2018;38(4):620-633. doi:10.1080/07388551.2017.1380598
8. What Is Glycerin? Food Insight. Published April 28, 2020. Accessed October 8, 2021. https://foodinsight.org/what-is-glycerin/

Up Next: Nature’s Sweetener: Allulose