The main principle of the CRD [carbohydrate-restricted diet] was to eliminate carbohydrate-rich food twice a day at breakfast and dinner, or eliminate it three times a day at breakfast, lunch and dinner... There were no other restrictions. Patients on the CRD were permitted to eat as much protein and fat as they wanted, including saturated fat.What happened to their blood lipids after eating all that fat for 6 months, and increasing their saturated fat intake to that of the average American? LDL decreased and HDL increased, both statistically significant. Oops. But that's water under the bridge. What we really care about here is glucose control. The patients' HbA1c (glycated hemoglobin; a measure of average blood glucose over the past several weeks) declined from 10.9 to 7.4%.
Here's a graph showing the improvement in HbA1c. Each line represents one individual:
Every single patient improved, except the "dropout" who stopped following the diet advice after 3 months (the one line that shoots back up at 6 months). And now, an inspirational anecdote from the paper:
One female patient had an increased physical activity level during the study period in spite of our instructions. However, her increase in physical activity was no more than one hour of walking per day, four days a week. She had implemented an 11% carbohydrate diet without any antidiabetic drug, and her HbA1c level decreased from 14.4% at baseline to 6.1% after 3 months and had been maintained at 5.5% after 6 months.That patient began with the highest HbA1c and ended with the lowest. Complete glucose control using only diet and exercise. It may not work for everyone, but it's effective in some cases. The study's conclusion:
...the 30%-carbohydrate diet over 6 months led to a remarkable reduction in HbA1c levels, even among outpatients with severe type 2 diabetes, without any insulin therapy, hospital care or increase in sulfonylureas. The effectiveness of the diet may be comparable to that of insulin therapy.
Diabetics on a Low-carbohydrate Diet
The Tokelau Island Migrant Study: Diabetes