Written by Chrystal Moulton, Staff Writer. Reduction in HbA1C reached near statistical significance in the low carb breakfast group compared to control (P= 0.06).
For individuals with type 2 diabetes, managing sugar throughout the day and after meals is essential to reducing the risk of developing cardiovascular disease and even lowering the risk of mortality1,2. Regulation of carbohydrate intake is important to controlling glucose3. A low carbohydrate diet has been suggested to improve glucose control; however, research shows that adherence to this kind of diet is low4. In the current trial5, researchers suggested applying low carbohydrate restriction to only one meal in order to improve glycemic control in Individuals living with type 2 diabetes. They hypothesized that applying a low carb breakfast without changing the remaining meals over three months could improve glycemic control in people with type 2 diabetes.
The study was conducted over 12 weeks at two sites (Australia and Canada) during the COVID-19 pandemic. Study design was a parallel arm randomized control trial. Participants were included if:
- Age: 20-79 years old
- HBA 1C < 8.5% ( 69 mmol/ L)
- Blood pressure < 164/99 mmHg
- BMI > 25kg/m2
- Diagnosed with type 2 diabetes ≥ 1 year
Participants were randomly assigned on a 1:1 basis to receive either low carbohydrate breakfast (25g protein, 8g carbohydrates, and 37g fat) or control breakfast (20g protein, 56g carbohydrates, and 15g fat) each morning. Participants in each group was provided a menu of 8-10 breakfast recipes to choose from. Upon choosing their breakfast options, they were required to upload a photograph of their breakfast every morning. Participants were also required to record three-day food records at week 1, at week 6, and at week 12. A dietitian reviewed all uploads and information to confirm compliance. Participants reported height, weight and waist circumference at the beginning and end of the trial. Blood samples were also collected at baseline and after week 12. A continuous glucose monitor (CGM) device was inserted into the upper arm in each participant to collect glucose readings every 15 minutes during the first and last two weeks of the trial. Participants also completed questionnaires reporting physical activity as well as hunger and satiety at week one, week 6, and week 12. The primary outcome was reduction in HbA1C at week 12. Data from the continuous glucose monitor (CGM) device was the secondary outcome.
A total of 127 participants were randomly assigned to the low carbohydrate breakfast (N = 64) or controlled breakfast group (N = 63). In the end, 93 participants completed the trial (LC group = 45, control = 48) and 121 participants data was included in the analysis. Participants assigned to the low carbohydrate breakfast group showed good compliance to their protocol (median =79 out of total 84 breakfasts). By week 12, participants in the low carb breakfast group showed a reduction in HbA1C compared to the control; however, the difference between the groups did not reach statistical significance (P = 0.06). No statistical differences were observed between the low carb and control groups for BMI, waist circumference, or weight. The continuous glucose monitor data (CGM device) showed significant improvement in mean glucose (P= 0.03), max glucose (P= 0.01), and glucose AUC (P= 0.02) in the low carb breakfast group compared to the control. Furthermore, mean amplitude of glycemic excursions (P = 0.002), glucose time in range (P= 0.02), and standard deviation (P = 0.009) were significantly better in the low carb breakfast group compared to control. Postprandial data following breakfast was also significantly better in mean glucose, max glucose, standard deviation, and AUC in the low carb breakfast group compared to a control (P <0.001). No significant difference was observed in physical activity, hunger, and satiety between the two groups.
Results from this study showed the simple addition of a low carb breakfast was well received (high adherence) among the participants with type 2 diabetes. HbA1C was not statistically significant between the low carb and control breakfast groups after three months. However, continuous glucose monitoring data showed that a low carb breakfast could support glycemic variability in people with type 2 diabetes. Additional studies will be needed to assess the benefits of low carb diet for glycemic control in type 2 diabetes.
Source: Oliveira, Barbara F., Courtney R. Chang, Kate Oetsch, Kaja Falkenhain, Kara Crampton, Matthew Stork, Malvinder Hoonjan, Thomas Elliott, Monique E. Francois, and Jonathan P. Little. “Impact of a Low-Carbohydrate Compared with Low-Fat Breakfast on Blood Glucose Control in Type 2 Diabetes: A Randomized Trial.” The American Journal of Clinical Nutrition (2023).
© 2023 American Society for Nutrition. Published by Elsevier Inc. All rights reserved
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Posted August 8, 2023.
Chrystal Moulton BA, PMP, is a 2008 graduate of the University of Illinois at Chicago. She graduated with a bachelor’s in psychology with a focus on premedical studies and is a licensed project manager. She currently resides in Indianapolis, IN.
References:
- Gin H, Rigalleau V. Post-prandial hyperglycemia. post-prandial hyperglycemia and diabetes. Diabetes & metabolism. Sep 2000;26(4):265-72.
- Ceriello A. Postprandial hyperglycemia and diabetes complications: is it time to treat? Diabetes. Jan 2005;54(1):1-7. doi:10.2337/diabetes.54.1.1
- Evert AB, Dennison M, Gardner CD, et al. Nutrition Therapy for Adults With Diabetes or Prediabetes: A Consensus Report. Diabetes Care. May 2019;42(5):731-754. doi:10.2337/dci19-0014
- Kumar NK, Merrill JD, Carlson S, German J, Yancy WS, Jr. Adherence to Low-Carbohydrate Diets in Patients with Diabetes: A Narrative Review. Diabetes Metab Syndr Obes. 2022;15:477-498. doi:10.2147/dmso.S292742
- Oliveira BF, Chang CR, Oetsch K, et al. Impact of a Low-Carbohydrate Compared with Low-Fat Breakfast on Blood Glucose Control in Type 2 Diabetes: A Randomized Trial. Am J Clin Nutr. Jul 2023;118(1):209-217. doi:10.1016/j.ajcnut.2023.04.032