A low-carbohydrate ketogenic diet is safe, effective, and superior to a low-calorie diet in type 2 diabetics, according to a report last year in Nutrition.
Kuwaiti researchers gave 102 adult overweight diabetic men and women their choice of diet: 78 chose ketogenic, 24 went low-calorie. Average age was 37, average weight 211 lb (96 kg). The study lasted six months. The ketogenic diet was very much Atkins-style, starting out at 20 grams of carbohydrate daily. Once good weight-loss progress was made, and if carb cravings were an issue, dieters could increase their carbs in small increments weekly.
This is all they said about the low-calorie diet: “Participants in the low-calorie diet group were given appropriate guidelines and a sample low-calorie diet menu of 2200 calories is presented in Table 1” (it’s typical and reasonable).
What Did They Find?
The low-carb ketogenic dieters lost 12% of body weight, compared to 7% lost by the low-calorie dieters. Furthermore, the ketogenic dieters showed significant lowering of total cholesterol, LDL cholesterol (bad cholesterol), and triglycerides. HDL cholesterol (good cholesterol) rose. The low-calorie dieters seem to have had a significant drop in LDL cholesterol, but no changes in the other lipids.
Fasting blood sugar levels dropped significantly in both groups, but more in the ketogenic dieters. Both groups started with fasting blood sugars around 162 mg/dl (9 mmol/l) and fell to 108 mg/dl (6 mmol/l) in the ketogenic group and to 126 mg/dl (7 mmol/l) in the low-calorie group.
Glycosylated hemoglobin (hemoglobin A1c) levels fell in both groups, more so in the ketogenic dieters. The drop was statistically significant in the ketogenic group, but the authors were unclear about that in the low-calorie dieters. It appears hemoglobin A1c fell from 7.8% to 6.3% with the ketogenic diet (the units given for glycosylated hemoglobin were stated as mg/dl). In the low-calorie dieters, hemoglobin A1c fell from 8.2 to 7.7%.
What’s Odd About This Study?
The title of the research report indicates a study of diabetics, but only about 25% of study participants had diabetes (total subjects = 363). (The figures I share above are for the diabetics only.)
Glycosylated hemoglobin, a test of overall diabetes control, is reported in Fig. 1 in terms of mg/dl. That’s nearly always reported as a percentage, not mg/dl. Misprint?
None of the participants dropped out of the study. That’s incredible, almost unbelievable.
The low-calorie diet was poorly described. Were 140-lb women and 250-lb men all put on the same calorie count?
Food diaries were kept, but the authors report nothing about compliance and actual food intake.
Clearly, some of these diabetics were on insulin and other diabetic drugs. The authors note necessary reductions in drug dosages for the ketogenic group but don’t say much about the other dieters. They imply that the drug reductions in the low-calorie group were minimal or nonexistent.
Calorie-restricted diets are effective in overweight type 2 diabetics, but ketogenic diets are even better.
The effectiveness and safety of ketogenic diets for overweight type 2 diabetics has been demonstrated in multiple other populations, so this study is not surprising. We’ve seen these lipid improvements before, too.
The favorable lipid changes on low-carb ketogenic diets would tend to reduce future heart and vascular disease.
I know little about Kuwaiti culture and genetics. Their contributions to the results here, as compared with other populations, is unclear to me. Type 2 diabetes is spreading quickly through the Persian Gulf, so this research may have wide applicability there.
Reference: Hussain, Talib, et al. Effect of low-calorie versus low-carbohydrate ketogenic diet in type 2 diabetes. Nutrition, 2012; 28(10): 1016-21. doi: 10.1016/j.nut.2012.01.016