Carbohydrate Restriction May Reverse Prediabetes 

Studies show that carbohydrate restriction for prediabetes can lead to normal glucose levels, reduce the progression to type 2 diabetes, and decrease the prevalence of metabolic syndrome. 

Before the diagnosis of type 2 diabetes, people may more than likely be initially diagnosed with prediabetes – blood sugar levels that are higher than usual, but not high enough to be classified as diabetes. Prediabetes puts patients at higher risks of developing type 2 diabetes and the complications associated with it. Therefore, according to the American Association of Clinical Endocrinologists (AACE), the goal is to normalize glucose levels to prevent and delay progression to diabetes and its complications. This is best achieved through intensive lifestyle management, which includes medical nutrition therapy. Medical nutrition therapy includes monitoring day-to-day carbohydrate intake and limiting high-glycemic foods. Carbohydrate restriction has been proven to be safe and effective in slowing the progression of type 2 diabetes. However, the multi-year effects on prediabetes are unknown. 

In a single-arm, prospective, longitudinal study, the effects of carbohydrate restriction were analyzed two years after treatment. This study was done with a remotely delivered continuous care intervention (CCI) that emphasized carbohydrate restriction and weight loss to patients with prediabetes. Researchers assessed the incidence of regression from prediabetes to normoglycemia, progression from prediabetes to type 2 diabetes, and the prevalence of metabolic syndrome after two years of treatment. 116 patients who were class II or greater obesity with prediabetes were enrolled in this study. Prediabetes was defined as HbA1c < 6.5% with metformin use of HbA1c 5.7-6.4% without diabetes medication.  

At two years, the crude incidence for the first occurrence of regression from prediabetes to normoglycemia was 47.6 cases per 100 person-years, with the estimated cumulative incidence of normoglycemia being 52.3%. One new case of type 2 diabetes each year was observed. The crude incidence of type 2 diabetes diagnosis was 1.5 cases per 100 person-years with the estimated cumulative incidence of type 2 diabetes at two years being 3%. The prevalence of metabolic syndrome was reduced from 94% to 30% at one year and 47% at two years (p < 4.4 x 10−16). Additionally, the prevalence of class II or more significant obesity was reduced from 67% to 38% at one and 39% at two years (p < 0.0013). 62.5 % were able to achieve 7% or more of weight loss. Based on the results of this study, researchers can potentially emphasize the use of a carbohydrate-restricted diet for the reversal of prediabetes with the use of a CCI. 

This study demonstrated that carbohydrate restriction would show benefits in patients with prediabetes. This intervention can normalize blood sugar levels and even reduce the incidence of type 2 diabetes diagnoses. Intervention while patients have prediabetes is just as important as if the patient already has type 2 diabetes. Blood sugar levels have to be monitored to prevent the progression of diabetes potentially. Prediabetes is reversible, while diabetes is not. This study appropriately analyzed a nonpharmacological method with the use of a CCI to prevent type 2 diabetes.  

The use of a CCI in patients with diabetes has already proven to be beneficial with glycemic control. The use of this method in this study strengthens the study. The real effect of carbohydrate restriction could be determined, and the results should be reliable based on the beneficial effects provided by the use of a CCI.   

Another thing to point out, though, is the willingness of patients to restrict their carbohydrates. A lot of people find that this diet is more challenging to stick to because many people’s favorite foods are loaded with carbohydrates. This study was conducted after two years of carbohydrate restriction. Were the patients willing to continue to restrict their carbohydrates once the study was completed? How long would people have to continue to restrict their carbohydrates to prevent the development of type 2 diabetes? The difficulty of the diet is something to include when analyzing the diet because adherence may become an issue.   

We need to let our patients with A1c’s in the prediabetic range know that with a small change in their nutrition and physical activity, they can prevent or at least delay the complications from diabetes and improve their quality of life as they get older. 

Practice Pearls: 

• Most patients with a diagnosis of type 2 diabetes were more than likely diagnosed with prediabetes first. 
• It is essential to treat prediabetes to prevent the progression of diabetes, and the complications associated with it, appropriately. 
• Carbohydrate restriction, along with a continuous care intervention, has shown to be effective in normalizing blood sugar levels in patients with prediabetes and also preventing the progression to type 2 diabetes. 

Mckenzie, A., Athinarayanan, S. J., Mccue, J., Adams, R. N., Mccarter, J. P., & Volek, J. (2020). 65-LB: Regression of Prediabetes following Two Years Treatment with a Continuous Care Intervention Emphasizing Carbohydrate Restriction: A Single-Arm, Prospe 

American Association of Clinical Endocrinologists. (n.d.). Retrieved August 03, 2020, from https://www.aace.com/disease-state-resources/diabetes/depth-information/management-prediabetes 

Brianna Belton, PharmD. Candidate, Florida Agricultural & Mechanical University, College of Pharmacy and Pharmaceutical Sciences