Diabetes is a disease where you have problems producing or using the hormone insulin (Type 2 Diabetes), or when your body doesn’t produce insulin at all (Type 1 Diabetes).
Insulin is the hormone that is produced to help your body absorb glucose, store glucose as glycogen, or store glucose as fat. The more glucose you consume, the more insulin your body will produce.
The exact causes of Type 2 Diabetes are unknown, but we do understand the primary risk factors to be weight, fat distribution, inactivity, family history, race, age, prediabetes, gestational diabetes, and polycystic ovarian syndrome. 
There have been a few studies on how the ketogenic diet impacts people with Type 2 Diabetes:
1.) In 2005, a study at Duke looked at 28 overweight people with type 2 diabetes. After 16 weeks of going on the Ketogenic Diet, receiving nutritional counseling, and reducing medictions – they found an average of 19 lbs lost, decreased blood glucose levels by 17%, and decreased triglyceride (fat) levels by 42%. 
2.) Another study compared results of Type 2 Diabetes between a low calorie diet and a Ketogenic Diet. Here is a table of the results: 
3.) Another study compared people without diabetes to determine how these diets might impact the risk of getting Type 2 Diabetes.  They put people into 3 different diet groups:
Here are some key results of this study:
- All diets produced similar body fat and weight loss.
- VLCARB was more effective in improving tracylglycerols, HDL cholesterol, fasting and post-meal glucose and insulin concentrations. More specifically, triacylglycerols decreased by 39.9% in VLCARB subjects, 4.0% in VLF subjects, and 9.6% in HUF subjects.
- Insulin levels decreased by 33.6% in VLCARB subjects, decreased by 18.7% in HUF subjects, and increased by 15.1% in VLF subjects.