Medically reviewed by Dr. Jordan Pinsker, Chief Medical Officer, Tandem Diabetes Care
There are three macronutrients that a body can break down for energy: Fats, proteins, and carbohydrates. Carbohydrates (often called “carbs”) are the fastest nutrient to break down during the digestion process, and therefore affect a body’s blood glucose level with the greatest impact. Maintaining a balanced diet, including a moderate amount of carbs, can help people with diabetes keep their blood sugars level and within a healthy range.
What are Carbohydrates?
At their molecular level, carbohydrates are composed of one carbon atom attached to one hydrogen atom. Various other atoms attach to this pair to create nuances in the complexity of the carbohydrate molecule. A more complex structure will take a body longer to break down during digestion. Sugar is the simplest form of carbohydrate and is therefore digested most quickly.
“Carbohydrates, or ‘carbs,’ are one of the main nutrients in the diet,” says Krista Kriegel, Sr. Director of Clinical Services at Tandem Diabetes Care. “Carbs are the starches, sugars, and fiber in the foods we eat. Within minutes of eating, the digestive system begins breaking carbohydrates down into glucose, which then enters the bloodstream.”
In the U.S., carbohydrates are measured in grams, with four calories of energy yielded per gram of carbohydrate. A serving of carbohydrate is considered 15 grams. Different foods contain different amounts of carbohydrates.
Carbs are present in many different foods but are found in higher concentrations in some food groups. Grains, fruits and fruit juices, and starchy vegetables contain some of the highest levels of carbohydrate by volume. Dairy products and non-starchy vegetables also contain carbs, but in lower concentrations. Highly processed foods, such as many snacks and desserts, often contain large quantities of carbohydrates, whereas meats contain far fewer carbs and more protein.
Diabetes and Carbohydrates
You can help your body regulate your blood sugar levels and overall health by eating a balance of carbohydrates, fats, and proteins through a variety of fresh and whole grain foods in all your meals.
“Carbohydrates do have the greatest impact on blood glucose so it’s important for someone living with diabetes to learn about carb counting,” Kriegel said. “Consuming too many carbs may lead to high blood glucose, and consuming too few carbs may lead to low blood glucose, especially in people who give themselves insulin.”
Many people living with diabetes find that carb counting is beneficial to maintaining good glucose control. The goal of carb counting is to understand how many carbs are in the foods that you are putting into your body, so you can better understand the effect that those foods will have on your glucose levels.
INSULIN-TO-CARB RATIO: A RELATIONSHIP
Everyone needs a hormone called insulin, which helps to regulate the amount of glucose in the bloodstream by allowing cells to absorb glucose and to further process it into energy. People living with type one diabetes (T1D) are either unable to use the insulin their body produces well, or cannot produce insulin at all, and must manually introduce insulin into the body via an injection, insulin pump infusion, or inhaler.
Check out our article for more information on how insulin works.
For people living with T1D, carb counting can help determine an accurate insulin-to-carb ratio, or a personalized measure of how many grams of carbs are offset by one unit of insulin. Talk to your healthcare provider to determine what your carb ratio should be, since this varies greatly from person to person and can change based on many factors.
If you have a Tandem insulin pump with Control-IQ technology, you can set a Personal Profile to have different carb ratios throughout the day to accurately deliver insulin for your meals.
THE GLYCEMIC INDEX: NUTRITIONAL CHOICES
The glycemic index is a method of determining how quickly a particular food can raise glucose.
A food with a high glycemic index will be digested and increase blood sugar levels quickly. High glycemic index foods include processed snacks, baked desserts like donuts and cakes, and processed starches and grains like white rice.
Alternatively, foods with a low glycemic index include many vegetables, whole-grain starches like barley or oats, and legumes. Low glycemic index foods can help even out blood sugar spikes because they do not raise blood sugars quickly. A balanced food plan will include many of these low glycemic index foods with the goal of consuming as many nutrients as possible, without adding extra glucose to the body.
“The glycemic index looks at individual foods, not meals, so it can be complicated to put into practice,” says Kriegel. “It’s best not to label carbs as all ‘good’ or all ‘bad.’ All foods can fit in the context of a healthy diet. However, many high glycemic index foods offer good nutrition and fiber, while others may not offer much nutritional value.”
MANAGING CARBOHYDRATES FOR BLOOD SUGAR CONTROL
There is no set amount of carbohydrates that a person living with diabetes should eat every day. People living with diabetes should work with a professional nutritionist or dietician to determine what foods may benefit their glycemic control and fit in well with their lifestyle. Healthcare professionals can also help to develop a personalized carb-counting plan based on foods you eat regularly. Together, you and your provider can create a diabetes-friendly meal plan that can help to reduce insulin resistance and prevent blood sugar spikes and crashes.
“Carbohydrates are an important part of a healthy diet for people with diabetes,” says Kriegel. “Carbohydrate-containing foods (like fruits, vegetables, milk, whole grains, to name a few) provide the body with important vitamins, minerals, and fiber.”
Carbohydrate-Counting Techniques and Tools
You can make a close estimate of the carbs a food contains by using several methods. You can make informed decisions about which foods to eat and how much insulin to take before your meals.
MEASURING OR WEIGHING FOOD TO DETERMINE CARBOHYDRATES
You can measure foods by size or volume to estimate the portion size and amount of carbohydrates. This can include using measuring cups or spoons or a small scale, but you can also use common items to estimate portion sizes. For example, one cup of food is about the same size as a fist.
It is recommended that even people with years of experience in estimating carbs use this method occasionally to check their estimation accuracy. Check out our Introduction to Carb Counting Quick Reference Sheet for more ideas on how to measure and weigh or estimate food portions.
HOW TO READ NUTRITION FACTS
Nutrition Facts labels are printed on the outside of all individual retail sale food packaging in the U.S. and show nutritional values contained in the packaged food. They include information like ingredients, serving size, and carbohydrate content. Look for the line near the top that reads “Serving Size” or “Per Serving” to see the recommended portion of food. You can then multiply the number of portions you plan to eat by the grams of carbohydrate per serving, found on the line labeled “Total Carbohydrate.” For a comprehensive tutorial on how to count carbohydrates, including instructions on how to read a nutrition label, check out our Introduction to Carb Counting video.
CARB GUIDES: PRINTED, ONLINE, AND APP RESOURCES
Many other resources exist to help with carb counting and estimating. These include flyers and quick reference sheets, books with lists of foods, and many mobile apps. Talk with your healthcare professional, nutritionist, or dietician for ideas on reference tools that may be helpful to you, or view our Carbohydrate List to get started.
Conclusion
Carbohydrates are a crucial component of a balanced diet. For people with T1D, they present a unique challenge in managing blood sugar levels. However, with proper understanding and planning, carbohydrates can help fuel your body’s energy supply and contribute to a healthy diet.
Unless otherwise noted, all medical information was provided by Jordan Pinsker, MD, Chief Medical Officer; Leah Fuller McLane, PharmD, BC-ADM, CDCES, Sr. Medical Science Liaison Manager; Amy Rich, Medical Science Liaison; and Krista Kriegel, MS, RD, CDCES, Sr. Director of Clinical Services, all of Tandem Diabetes Care, Inc.
Responsible Use of Control-IQ Technology: Control-IQ technology does not prevent all highs and lows. You must still bolus for meals and actively manage your diabetes. Please visit tandemdiabetes.com/responsible-use for more information.
Important Safety Information
RX ONLY.
Indications for Use:
Tandem Mobi system: The Tandem Mobi insulin pump with interoperable technology (the pump) is intended for the subcutaneous delivery of insulin, at set and variable rates, for the management of diabetes mellitus in persons requiring insulin. The pump is able to reliably and securely communicate with compatible, digitally connected devices, including automated insulin dosing software, to receive, execute, and confirm commands from these devices. The pump is intended for single patient, home use and requires a prescription. The pump is indicated for use in individuals 6 years of age and greater.
t:slim X2 insulin pump: The t:slim X2 insulin pump with interoperable technology is intended for the subcutaneous delivery of insulin, at set and variable rates, for the management of diabetes mellitus in people requiring insulin. The pump is able to reliably and securely communicate with compatible, digitally connected devices, including automated insulin dosing software, to receive, execute, and confirm commands from these devices. The pump is intended for single patient use. The pump is indicated for use with NovoLog or Humalog U-100 insulin. The pump is indicated for use in individuals 6 years of age and greater.
Control-IQ technology: Control-IQ technology is intended for use with compatible integrated continuous glucose monitors (iCGM, sold separately) and alternate controller enabled (ACE) pumps to automatically increase, decrease, and suspend delivery of basal insulin based on iCGM readings and predicted glucose values. It can also deliver correction boluses when the glucose value is predicted to exceed a predefined threshold. Control-IQ technology is intended for the management of Type 1 diabetes mellitus in persons 6 years of age and greater. Control-IQ technology is intended for single patient use. Control-IQ technology is indicated for use with NovoLog or Humalog U-100 insulin.
Warning: Control-IQ technology should not be used by anyone under the age of 6 years old. It should also not be used in patients who require less than 10 units of insulin per day or who weigh less than 55 pounds.
Control-IQ technology is not indicated for use in pregnant women, people on dialysis, or critically ill patients. Do not use Control-IQ technology if using hydroxyurea. Users of a Tandem insulin pump and Control-IQ technology must use the insulin pump, CGM, and all other system components in accordance with their respective instructions for use; test blood glucose levels as recommended by their healthcare provider; demonstrate adequate carb-counting skills; maintain sufficient diabetes self-care skills; see healthcare provider(s) regularly; and have adequate vision and/or hearing to recognize all functions of the pump, including alerts, alarms, and reminders. The Tandem pump and the CGM transmitter and sensor must be removed before MRI, CT, or diathermy treatment. Visit tandemdiabetes.com/safetyinfo for additional important safety information.
