If not managed correctly, high blood sugar in diabetics can damage blood vessels and lead to a variety of illnesses. Unmanaged diabetes doubles the risk of cardiovascular diseases such as coronary artery diseases and stroke. [3, 4] Diabetes can damage small vessels in the eyes, kidneys, and nerves and lead to complications such as blindness and kidney disease. 
As Tammy points out, diets are diets, and many people nowadays think/feel that diets are a “time/value-based goal”. “If I just get my weight down, or if I just fix this, then I’ll be all set…” WRONG!!! There in lies the first problem. How long can it be maintained? Well that’s a good point. The real question is, how long is one committed to changing their life, and how strong is their desire to do it. ALL things that one wants to change in life, require a change in to the way their living and/or perceiving life. They require a life-style change. One could attempt a Mediterranean diet, and yet relapse back to “normal” eating after 3mos, 1yr, 3yrs, etc.. It doesn’t really matter if the change isn’t first on the mental and emotional level. Unfortunately, many first-world daily diets (namely American) incorporate many foods that are addictive which can cause cravings. And yes, the cravings are scientifically prove-able, and have been proved. We grow up thinking that it’s “normal” to have your cake (since its the carb of debate lol) and eat it too, because why?… Well because that’s how they were raised. Simply as that. Conditioned living if you will. There are many cultures on this planet that DO NOT grow up eating as many carbs and sweets as the American Diet, and do perfectly fine without all the sugars and carb cravings. And incidentally, they also lead healthier lives too… Go figure.
A ketogenic diet helps control blood sugar levels. It is excellent for managing type 2 diabetes, sometimes even leading to complete reversal of the disease. This has been proven in studies. It makes perfect sense since keto lowers blood-sugar levels, reduces the need of medications and reduces the potentially negative impact of high insulin levels.