Studies have shown that the ketogenic diet provides many therapeutic benefits, including reduced insulin and blood sugar levels. A 2008 study of 49 people with type 2 diabetes found that those put on a ketogenic diet had a larger reduction in blood sugar levels (approximate 1.5%) than those on a calorie-restricted diet.
Reference: Bolla AM, Caretto A, Laurenzi A, Scavini M, Piemonti L. Low-Carb and Ketogenic Diets in Type 1 and Type 2 Diabetes. Nutrients. 2019;11(5):962. Published 2019 Apr 26. doi:10.3390/nu11050962.