HbA1c (glycated haemoglobin) is the most important long-term measure of blood sugar control. For people with Type 2 diabetes or prediabetes, reducing HbA1c is the primary goal of treatment. The ketogenic diet is one of the most effective dietary interventions for lowering HbA1c.
HbA1c reflects average blood glucose levels over the previous 2-3 months. It’s measured as a percentage or in mmol/mol. A normal HbA1c is below 42 mmol/mol (6%). Prediabetes is 42-47 mmol/mol. Type 2 diabetes is 48 mmol/mol or above. Every 1% reduction in HbA1c significantly reduces the risk of diabetes complications.
By keeping blood glucose consistently low through carbohydrate restriction, keto directly reduces the amount of glucose that attaches to haemoglobin. Less dietary glucose = lower blood sugar = lower HbA1c. Clinical studies show average HbA1c reductions of 1.0-1.5% (11-16 mmol/mol) in Type 2 diabetics following a ketogenic diet for 12 weeks.
Ask your GP for an HbA1c test before starting keto and again after 3 months. Most people see significant improvements within the first 3-month period. Keep a record of your readings and share them with your healthcare team — medication adjustments are often needed as blood sugar improves. Explore our keto main dish recipes for blood glucose-friendly meals and check our keto salad recipes for nutrient-dense low-GI options.