This article will discuss carbohydrates and their impact on blood sugar and insulin. You’ll learn the ideal amount of carbs diabetics should aim for and the best diets you can follow to optimize your blood sugar and your health.
Carbs, Insulin, and Diabetes
Carbohydrates are the most abundant macronutrient in our diet, making up approximately 46% of the calories adults consume in the US.1 There are three main types of carbs: sugar, starch, and fiber. Sugar is considered a simple carb and is found naturally in foods and beverages like fruit, milk, and honey. Added sugars are also found in processed foods like candy and baked goods.
Starches and fiber are considered complex carbs. The human body takes more time to digest these types of carbohydrates. Starches can be found in vegetables like potatoes and corn, as well as legumes and whole grain bread products. Fiber is found naturally in fruits, vegetables, legumes, nuts, and whole grains.
Eating excess carbohydrates (both simple and complex) can cause blood sugar spikes, which triggers the pancreas to produce insulin. Insulin acts like a key that opens a lock and allows glucose to enter into cells from the bloodstream. Over time, elevated blood sugar can cause damage to endothelial tissue and can even cause damage to organs like the heart and kidneys.2
Frequent high blood sugar also requires the pancreas to work harder to pump out sufficient insulin. Chronic high insulin levels can eventually make our cells less sensitive to insulin, creating a vicious cycle in which the body requires even higher insulin levels, and the pancreas can’t keep up.3 Type 2 diabetes develops due to insulin resistance and inadequate insulin production.
Why Should Someone Living With Diabetes Count Carbs?
If you’ve been diagnosed with diabetes, managing your blood sugar is essential. Being mindful of what you’re eating and how it impacts your blood glucose will help reduce your risk of serious (and sometimes fatal) complications.
In individuals living with type 2 diabetes, the way the body metabolizes glucose is altered, which can lead to big swings in blood sugar. These fluctuations can impact mood and quality of life and increase the risk of retinopathy and atherosclerosis.4,5 For diabetes management, it is critical to determine the right balance of carbohydrate intake and the type of carb that should be ingested.
How Many Carbs Should You Eat If You Have Type 2 Diabetes?
The American Diabetes Association (ADA) recommends considering factors like age, weight, and activity level to determine the ideal number of carbohydrates you should consume. Individual response to glucose varies from person to person, so it’s important to work with your doctor or dietitian to determine the specific amount that’s right for you.
While the exact amount of carbohydrates per day needs to be personalized for each patient, increasing evidence supports low-carb diets for managing diabetes. A “low carbohydrate diet” is a general term usually referring to diets comprising less than 100 grams of carbs per day.
Studies have shown that for people with type 2 diabetes, low-carbohydrate diets can:6,7,8
- Reduce the need for medication
- Lower hemoglobinA1C (HbA1C)
- Support weight loss
- Increase insulin sensitivity
- Decrease triglycerides
The average American consumes 2,200 calories per day with 50% coming from carb sources.14 A restricted intake of less than 50 grams per day (about 8-10% of daily calories on a 2,000-2,220 calorie diet) may reduce or eliminate the need for insulin or diabetes medication.15,16,17
Which Low-Carb Diet is Best?
Traditionally, when people think of low-carb diets, they may picture monotonous meals and large amounts of meat, but there are now many versions.
Although following a new diet can be challenging, those who take this approach will have an array of options to choose from.
Below are examples of a few different low-carb diets. All three of these eating patterns suggest avoiding processed and highly processed foods including soft drinks, fruit juices, processed cooking oils, and candy.
- Ketogenic (Very Low Carb)
This eating plan focuses on meals and snacks with high amounts of fat, moderate protein, and very low amounts of carbs. It typically limits people to 20-50 grams of carbs per day.9 The keto diet has been shown to increase insulin sensitivity and improve glycemic control in patients with diabetes.10
Some concerns have been raised that consuming high amounts of protein on a low-carb diet may lead to kidney issues. However, a 12-month study found that very low carb intake did not increase the risk of kidney disease.18 Also, another study found that this eating pattern may improve kidney function in those living with type 2 diabetes.19
- Paleo (Low Carb)
The Paleo diet is intended to mimic the diets of our hunter-gatherer ancestors and recommends consuming 130 grams of carbs or less per day. People following this diet can enjoy a greater variety of fruits and vegetables than those following the ketogenic diet. Foods include a variety of plant-based fat, grass-fed and sustainably caught proteins, and almost all fruits and non-starchy vegetables. Studies have also shown that the Paleo diet may reduce HbA1C, lower triglycerides, and reduce triglycerides.11
- Mediterranean (Moderate Carb)
This popular diet encourages lean protein like fish and healthy fats like olive oil. It differs from the previously mentioned diets because it also allows for a variety of whole grains, beans, nuts, fruits, and vegetables. People following the Mediterranean diet consume about 200 grams of carbohydrates daily. This diet has been shown to support weight loss, lower HbA1c, and improve cholesterol.12
Carb Counting: How to Determine Optimal Carb Intake for Diabetes
Carb counting is a way to measure the grams of carbohydrates you’re consuming each day. This will help prevent blood sugar levels from spiking and allow you to better manage your diabetes.
To do this, you’ll need to measure your food and pay attention to nutrition labels carefully. You may need to look up information online for food that doesn’t have labels. If you do this, be sure to use trusted sources. Identify the total number of grams of carbohydrates for each meal and snack.
Here are some tips to help you count and keep track effectively:
- Utilize the glycemic index (GI). This scale measures how quickly a food could raise blood sugar levels based on their carb intake and structure.
- Write down the number of carbs you’re eating at each meal and snack so you can keep a running total.
- Buy a kitchen scale and measuring cups to help with carbohydrate counting. These tools will also help you calculate the exact amount of carbs you utilize while cooking.
- When reading food labels, pay attention to portion sizes.
- Work with your healthcare provider to adjust your medication if necessary.
When to Consult a Professional
Finding the right balance of carbohydrates is important. Eating too many carbs can lead to chronic high blood glucose levels (hyperglycemia), and eating too few can cause your blood sugar to drop and possibly cause hypoglycemia. Consult with a registered dietitian or your healthcare provider to find the right amount for your specific situation.
You should also talk to your doctor right away if you’re experiencing any of the following:13
- Blurred vision
- Frequent urination
- Extreme thirst
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Topics discussed in this article:
- Centers for Disease Control and Prevention. (2023, May 17). FastStats- diet/nutrition. https://www.cdc.gov/nchs/fastats/diet.htm
- Wang, M., Li, Y., Li, S., & Lv, J. (2022). Endothelial dysfunction and diabetic cardiomyopathy. Frontiers in Endocrinology, 13. https://doi.org/10.3389/fendo.2022.851941
- Cleveland Clinic. (2021, Dec. 16). Insulin resistance. https://my.clevelandclinic.org/health/diseases/22206-insulin-resistance
- Dandona P. (2017). Minimizing Glycemic Fluctuations in Patients with Type 2 Diabetes: Approaches and Importance. Diabetes technology & therapeutics, 19(9), 498–506. https://doi.org/10.1089/dia.2016.0372
- Rask-Madsen, C., & King, G. L. (2013). Vascular complications of diabetes: mechanisms of injury and protective factors. Cell metabolism, 17(1), 20–33. https://doi.org/10.1016/j.cmet.2012.11.012
- Wheatley, S., Deakin, T., Arjomandkhah, N., Hollinrake, P., & Reeves, T. E. (2021). Low carbohydrate Dietary Approaches for People with Type 2 Diabetes—A Narrative Review. Frontiers in Nutrition, 8. https://doi.org/10.3389/fnut.2021.687658
- Dorans, K., Bazzano, L. A., Qi, L., He, H., Chen, J., Appel, L. J., Chen, C., Hsieh, M., Hu, F. B., Mills, K. T., Nguyen, B. T., O’Brien, M. J., Samet, J. M., Uwaifo, G. I., & He, J. (2022). Effects of a Low-Carbohydrate Dietary Intervention on Hemoglobin A1c. JAMA Network Open, 5(10), e2238645. https://doi.org/10.1001/jamanetworkopen.2022.38645
- Goldenberg, J. Z., Day, A. S., Brinkworth, G. D., Sato, J., Yamada, S., Jönsson, T., Beardsley, J., Johnson, J., Thabane, L., & Johnston, B. C. (2021). Efficacy and safety of low and very low carbohydrate diets for type 2 diabetes remission: systematic review and meta-analysis of published and unpublished randomized trial data. BMJ, m4743. https://doi.org/10.1136/bmj.m4743
- The Nutrition Source. (2019, May 22). Diet review: Ketogenic diet for weight loss. https://www.hsph.harvard.edu/nutritionsource/healthy-weight/diet-reviews/ketogenic-diet
- Gupta, L., Khandelwal, D., Kalra, S., Gupta, P., Dutta, D., & Aggarwal, S. (2017). Ketogenic diet in endocrine disorders: Current perspectives. Journal of postgraduate medicine, 63(4), 242–251. https://doi.org/10.4103/jpgm.JPGM_16_17
- Klonoff D. C. (2009). The beneficial effects of a Paleolithic diet on type 2 diabetes and other risk factors for cardiovascular disease. Journal of diabetes science and technology, 3(6), 1229–1232. https://doi.org/10.1177/193229680900300601
- News Center. (2022, July 8). Keto and Mediterranean diets both help manage diabetes, but one is easier to maintain. https://med.stanford.edu/news/all-news/2022/070/keto-mediterranean-diet-diabetes.html
- Mayo Clinic. (2023, March 14). Type 2 diabetes- Diagnosis and treatment. https://www.mayoclinic.org/diseases-conditions/type-2-diabetes/diagnosis-treatment/drc-20351199
- Merrill, J., Soliman, D., Kumar, N. K., Lim, S., Shariff, A., & Yancy, W. S. (2020). Low-Carbohydrate and Very-Low-Carbohydrate diets in patients with diabetes. Diabetes Spectrum, 33(2), 133–142. https://doi.org/10.2337/ds19-0070
- Murdoch, C., Unwin, D., Cavan, D., Cucuzzella, M., & Patel, M. (2019). Adapting diabetes medication for low carbohydrate management of type 2 diabetes: a practical guide. British Journal of General Practice, 69(684), 360–361. https://doi.org/10.3399/bjgp19x704525
- Snorgaard, O., Poulsen, G., Andersen, H., & Astrup, A. (2017). Systematic review and meta-analysis of dietary carbohydrate restriction in patients with type 2 diabetes. BMJ Open Diabetes Research & Care, 5(1), e000354. https://doi.org/10.1136/bmjdrc-2016-000354
- Cucuzzella, M., Riley, K., & Isaacs, D. (2021). Adapting medication for type 2 diabetes to a low carbohydrate diet. Frontiers in Nutrition, 8. https://doi.org/10.3389/fnut.2021.688540
- Tay, J., Thompson, C., Luscombe-Marsh, N. D., Noakes, M., Buckley, J. D., Wittert, G., & Brinkworth, G. D. (2015). Long-Term effects of a very low carbohydrate compared with a high carbohydrate diet on renal function in individuals with type 2 diabetes. Medicine, 94(47), e2181. https://doi.org/10.1097/md.0000000000002181
- Unwin, D., Unwin, J., Crocombe, D., Delon, C., Guess, N., & Wong, C. W. (2021). Renal function in patients following a low carbohydrate diet for type 2 diabetes: a review of the literature and analysis of routine clinical data from a primary care service over 7 years. Current Opinion in Endocrinology, Diabetes and Obesity, 28(5), 469–479. https://doi.org/10.1097/med.0000000000000658