Understanding Carbs and Their Effect on Blood Sugar

Understanding Carbs

Carbohydrates are a wonderful, nourishing, enjoyable part of our diet. As much as they have been in popular nutrition commentary in the past several years, it’s easy to get confused about their role in supporting our body’s nutrition needs as well as their impact on health. Flashback to the 1990s when dietary fats were to be avoided at all costs, and how much nourishing foods like nuts and avocados were the so-called “fat bombs” to avoid.

While many people with diabetes find that adopting a low-carb lifestyle helps with overall diabetes management, it’s helpful to consider that carbs include a wide range of foods with varying nutritional values and impacts on overall health.

There are three main types of carbs:

1. Starches

Starches, also called complex carbs, include foods such as potatoes, rice, pasta, bread, and whole grain cereals. Vegetable forms of starches include peas and corn, which add great sources of fiber and nutrients to our diets. This is a large category of carbohydrate, and the method of preparation, portion size, other foods consumed alongside these foods, and the sequence of consumption within a meal can affect blood glucose responses, along with other factors such as hydration level, medications, and activity levels.  In general, starches that are less processed tend to raise blood sugar more slowly (such as the starch in beans or peas vs. cotton candy). These starchy foods, which I often refer to as “carbs with benefits”, take a bit longer for our digestive system to break down for absorption. The gel type (or viscous fibers that are along for the ride with these nourishing foods) also impact glucose level less and are considered “prebiotics”, which feed the good bacteria in our intestinal tract and are associated with better heart, liver, and kidney function, as well as improved immunity due to the protection of the intestinal barrier function.

2. Simple Sugars

Simple sugars are found in items like glucose tablets/gels, fruit/fruit juices, honey, molasses, white and brown sugars, and syrups. Simple sugars can be consumed alone or added to foods. They can raise blood sugar levels more quickly than starches depending on a variety of factors, like other ingredients in the item and how quickly they are digested. For example, fruit is about 90 percent water. It has fiber, it takes time to chew, and it takes time to be broken up in the digestive tract. Juicing eliminates the mechanical work of chewing, so fruit juices (and other liquids with sugars) flow more easily and quickly into the intestinal tract for digestion and absorption. These factors can impact how quickly your blood glucose level rises after consumption. Some simple sugar products such as glucose gels, tablets, or hard candies act quickly and can be important to have on hand for those who may be at risk for hypoglycemia.

3. Fiber

Fiber is the non-digestible component of carbohydrate foods like fruits, vegetables, whole grains, beans, nuts, and seeds. It isn’t broken down and absorbed by the GI tract – it passes through undigested and for the most part intact by the time it reaches the colon (the large intestine). There are two main types of fiber: soluble (a gel or viscous type of fiber that can level out blood glucose levels and help lower cholesterol), and insoluble fiber such as bran, which adds bulk to the stool and can aid in regularity. Most people should aim for 25 to 30 grams of fiber per day. Currently, dietary fiber intake among adults in the United States averages about 15 grams per day. Foods with fiber – especially soluble (otherwise known as viscous or gel type fiber), may be helpful in stabilizing blood sugar levels because of a decreased rate of digestion and absorption of sugars and potentially improved insulin sensitivity- benefitting how well the insulin you make or take works.

Nutrition labels list total carbohydrates in the portion size referenced and should be used in carbohydrate counting if you are using this as part of insulin dosing. Remember, these are estimates and not exact. If a nutrition label isn’t available, websites or apps such as MyFitnessPal, Fooducate or CalorieKing can be helpful.

For the most part, choosing carbs that also provide supportive nutrition components such as vitamins, minerals, and fiber that have lower added sugars and saturated fats is preferable. But remember, one food does not make or break one’s health- it’s patterns of eating that make the difference.

Remember to Keep It in Balance

If you’re taking part in a lovely holiday or celebration, a special food that is symbolic and meaningful to the occasion is more “healthful” than bringing your own bag of kale to eat instead. Food is joy, love, and tradition, and having a peaceful and relaxed relationship with food is also a highly significant contributor to health.

On-the-Go Options with Lower Carbs

For some people, time and convenience are also important when it comes to making food choices. Ready-to-eat products like Glucerna shakes and bars can be tasty and dependable meal and snack replacement options that have a balance of nutrients and can produce a smaller peak in blood sugar levels than higher glycemic carbohydrate sources. As with all carbohydrate sources- simple or complex- portion size matters as well. One serving of a Glucerna Protein Smart Shake with 150 calories, 7 grams of total carbohydrate, 4 grams of dietary fiber, 3 grams of sugar, and 30 grams of protein can be a great start to your day, in comparison to a large muffin at approximately 437 calories, 76 grams of total carbohydrate, 7 grams of fiber, 24 grams of sugar and 8.5 grams of protein. This can potentially make a difference with glucose control, overall nutrition needs, and health goals.

How Many Carbs Should You Eat?

How many carbs do you need per meal? Everyone’s needs differ according to age, activity level, medical situations, goals of care, food budget, culture, preferences, and what is sustainable. Consult with a Registered Dietitian/Nutritionist for personalized and evidence-based recommendations that you can live with.  Just as our bodies change with age, our nutrition needs change as we age as well, and there’s no “one size fits all” diet for diabetes management.


Created in partnership with Abbott Nutrition, a sponsor of TCOYD at the time of writing.


Additional Resources:

Fiber: Carbs with Extra Benefits!

Counting Carbs Is a Crapshoot!

Strike the Spike: Controlling Blood Sugars After Eating

Carbs vs. Calories: Don’t Be Out to Lunch!

Hidden Names for Added Sugar

Nutrition and Type 2 Diabetes – Videos

Nutrition and Type 1 Diabetes – Videos

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