I would tell you what physician's journal I got this from, but I can't re-find it! (Common problem here on the Internet for me!)
From a peer-reviewed article: In a short-term study: "People on the low-fat vegan diet reduced their HbA1C levels by 1.23 points, compared with 0.38 points for the people on the American Diabetes Association diet. In addition, 43% of people on the low-fat vegan diet were able to reduce their medication, compared with 26% of those on the American Diabetes Association diet."
They also documented the results of one person who changed to a low fat vegan diet: "This shows a dramatic example of the effect a plant-based diet can have on biometric outcomes like blood pressure, diabetes, and lipid profile. The reduction in HbA1C from 11.1% to 6.3% in 3 months is much better than would be expected with monotherapy with metformin6 or daily exercise."
So basically what I have read about in several places is that many people with Type II diabetes end up cured and on no medication after switching to a low-fat vegan diet. This diet should gain some validity for how healthy it is instead of being looked at as a diet of skinny crazy hippies.