Dr. Eric Westman has been a vocal proponent of carbohydrate restriction to gain control over diabetes, as have Drs. Richard Bernstein, Mary Vernon, Richard Feinman, and Jeff Volek.
Several studies over the years have demonstrated that reductions in carbohydrate content of the diet yield reductions in weight and HbA1c (glycated hemoglobin, a reflection of average blood glucose over the preceding 60-90 days).
Among the more important recent clinical studies is a small experience from Duke University's Dr. Eric Westman. In this study, obese type 2 diabetics reduced carbohydrate intake to 20 grams per day or less: no wheat, oats, cornstarch, or sugars. Participants ate nuts, cheese, meats, eggs, and non-starchy vegetables.
After 6 months, average weight loss was 24.4 lbs, BMI was reduced from 37.8 to 34.4. At the end of the study, 95% of participants on this severe carbohydrate restriction reduced or eliminated their diabetes medications.
That was only after 6 months. Note that the ending BMI was still quite well into the obese range. Imagine what another 6-12 months would do, or achieving BMI somewhere closer to ideal.
Curiously, this idea of severe low-carbohydrate restriction to cure or minimize diabetes is not new. Sir William Osler, one of the founders of Johns Hopkins Hospital and author of the longstanding authoritative text, Principles and Practice of Medicine, advocated an diet identical to Dr. Westman's diet. So did Dr. Frederick Banting, discoverer of the pancreatic extract, insulin, to treat childhood diabetics. Before insulin, Banting and his colleagues at the University of Toronto used carbohydrate elimination (less than 10 g per day) to prolong the lives of children with diabetes.
This lesson was also learned many times during war time, when staples like bread were unavailable. The Siege of Paris in 1870 yielded cures for diabetes in many (or at least they stopped passing urine that tasted--yes, tasted--sweet and attracted flies), only to have it recur after the siege was over.
These are lessons we will have to relearn. As long as the American Diabetes Association and most physicians continue to advocate a diet of reduced fat, increased carbohydrate that includes plenty of "healthy whole grains," diabetics will continue to be diabetics, taking their insulin and multiple medications while developing neuropathy (nervous system degeneration), nephropathy (kidney disease and failure), atherosclerosis and heart attack, cataracts, and die 8 to 10 years earlier than non-diabetics.
All the while, we've had the combined wisdom from antiquity onwards: Carbohydrates cause diabetes; elimination of carbohydrates cures diabetes.
(This applies, of course, only to adult overweight type 2 diabetics, not type 1 or some of the other variants.)