Friday, September 3, 2010

Lasting Benefit

Dr. Eades commenting on the Israeli study:
"Despite the instruction to increase carbs to 120 grams per day, I believe these subjects had a long-term benefit from the two months of rigid low-carb dieting (20 grams per day) with which they started the study. Why do I believe that? There is a terrific study in Nutrition & Metabolism showing that subjects with diabetes who underwent a strictly supervised low-carb diet for six months, and who lost weight, improved blood sugar control and lipid parameters, were still showing the positive effects of this intervention 44 months later. These impressive findings seem to indicate that there is some sort of rejuvenation that takes place in people after they have spent a period of time on an honest-to-God low-carb diet that carries over for several years. Maybe this is the phenomenon we're seeing in the subjects in this NEJM study. The two months of rigid low-carb carries over for the rest of the study despite the subjects cranking their carbs up to non-low-carb levels."

The cited study is here:
Abstract:  Low-carbohydrate diets, due to their potent antihyperglycemic effect, are an intuitively attractive approach to the management of obese patients with type 2 diabetes. We previously reported that a 20% carbohydrate diet was significantly superior to a 55–60% carbohydrate diet with regard to bodyweight and glycemic control in 2 groups of obese diabetes patients observed closely over 6 months (intervention group, n = 16; controls, n = 15) and we reported maintenance of these gains after 22 months. The present study documents the degree to which these changes were preserved in the low-carbohydrate group after 44 months observation time, without close follow-up. In addition, we assessed the performance of the two thirds of control patients from the high-carbohydrate diet group that had changed to a low-carbohydrate diet after the initial 6 month observation period. We report cardiovascular outcome for the low-carbohydrate group as well as the control patients who did not change to a low-carbohydrate diet.
Retrospective follow-up of previously studied subjects on a low carbohydrate diet.
The mean bodyweight at the start of the initial study was 100.6 ± 14.7 kg. At six months it was 89.2 ± 14.3 kg. From 6 to 22 months, mean bodyweight had increased by 2.7 ± 4.2 kg to an average of 92.0 ± 14.0 kg. At 44 months average weight has increased from baseline g to 93.1 ± 14.5 kg. Of the sixteen patients, five have retained or reduced bodyweight since the 22 month point and all but one have lower weight at 44 months than at start. The initial mean HbA1c was 8.0 ± 1.5%. After 6, 12 and 22 months, HbA1c was 6.1 ± 1.0%, 7.0 ± 1.3% and 6.9 ± 1.1% respectively. After 44 months mean HbA1c is 6.8 ± 1.3%.
Of the 23 patients who have used a low-carbohydrate diet and for whom we have long-term data, two have suffered a cardiovascular event while four of the six controls who never changed diet have suffered several cardiovascular events.
Advice to obese patients with type 2 diabetes to follow a 20% carbohydrate diet with some caloric restriction has lasting effects on bodyweight and glycemic control.

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