A randomized pilot trial of a moderate carbohydrate diet compared to a very low carbohydrate diet in overweight or obese individuals with type 2 diabetes mellitus or prediabetes.
Study Goal
The researchers aimed to compare the effects of a very low carbohydrate, high fat diet (LCK) versus a medium carbohydrate, low fat diet (MCCR) on glycemic control and health outcomes in overweight or obese adults with type 2 diabetes or prediabetes.
Results Summary
The LCK diet significantly reduced HbA1c levels (-0.6%) compared to no change in the MCCR group, with more participants discontinuing diabetes medications (44% vs. 11%). The LCK group also lost more weight (5.5 kg vs. 2.6 kg), though this difference was not statistically significant.
Population
Overweight or obese adults with type 2 diabetes or prediabetes (HbA1c >6%), excluding insulin users.
Effective Dosage
Not specified (dietary intervention without fixed dosage).
Duration
3 months
Interactions
None mentioned
| Intervention | Direction | Endpoint | Population | Dosage | Impact | Claim # |
|---|---|---|---|---|---|---|
medium carbohydrate, low fat, calorie-restricted, carbohydrate counting diet (MCCR) | no change | mean HbA1c level | overweight or obese adults with type 2 diabetes or prediabetes (HbA1c>6%) | - | unchanged from baseline | #1 |
very low carbohydrate, high fat, non calorie-restricted diet whose goal was to induce nutritional ketosis (LCK) | decrease | mean HbA1c level | overweight or obese adults with type 2 diabetes or prediabetes (HbA1c>6%) | 0.6% | decreased | #2 |
very low carbohydrate, high fat, non calorie-restricted diet whose goal was to induce nutritional ketosis (LCK) | decrease | HbA1c change | overweight or obese adults with type 2 diabetes or prediabetes (HbA1c>6%) | -0.6%, 95% CI, -1.1% to -0.03% | significant between group difference in HbA1c change favoring | #3 |
very low carbohydrate, high fat, non calorie-restricted diet whose goal was to induce nutritional ketosis (LCK) | decrease | diabetes medications | overweight or obese adults with type 2 diabetes or prediabetes (HbA1c>6%) | 44% | 44% discontinued one or more diabetes medications | #4 |
medium carbohydrate, low fat, calorie-restricted, carbohydrate counting diet (MCCR) | decrease | diabetes medications | overweight or obese adults with type 2 diabetes or prediabetes (HbA1c>6%) | 11% | 11% discontinued one or more diabetes medications | #5 |
very low carbohydrate, high fat, non calorie-restricted diet whose goal was to induce nutritional ketosis (LCK) | decrease | sulfonylureas | overweight or obese adults with type 2 diabetes or prediabetes (HbA1c>6%) | 31% | 31% discontinued sulfonylureas | #6 |
medium carbohydrate, low fat, calorie-restricted, carbohydrate counting diet (MCCR) | decrease | sulfonylureas | overweight or obese adults with type 2 diabetes or prediabetes (HbA1c>6%) | 5% | 5% discontinued sulfonylureas | #7 |
very low carbohydrate, high fat, non calorie-restricted diet whose goal was to induce nutritional ketosis (LCK) | decrease | weight | overweight or obese adults with type 2 diabetes or prediabetes (HbA1c>6%) | 5.5 kg | lost | #8 |
medium carbohydrate, low fat, calorie-restricted, carbohydrate counting diet (MCCR) | decrease | weight | overweight or obese adults with type 2 diabetes or prediabetes (HbA1c>6%) | 2.6 kg | lost | #9 |
We compared the effects of two diets on glycated hemoglobin (HbA1c) and other health-related outcomes in overweight or obese adults with type 2 diabetes or prediabetes (HbA1c>6%). We randomized participants to either a medium carbohydrate, low fat, calorie-restricted, carbohydrate counting diet (MCCR) consistent with guidelines from the American Diabetes Association (n = 18) or a very low carbohydrate, high fat, non calorie-restricted diet whose goal was to induce nutritional ketosis (LCK, n = 16). We excluded participants receiving insulin; 74% were taking oral diabetes medications. Groups met for 13 sessions over 3 months and were taught diet information and psychological skills to promote behavior change and maintenance. At 3 months, mean HbA1c level was unchanged from baseline in the MCCR diet group, while it decreased 0.6% in the LCK group; there was a significant between group difference in HbA1c change favoring the LCK group (-0.6%, 95% CI, -1.1% to -0.03%, p = 0.04). Forty-four percent of the LCK group discontinued one or more diabetes medications, compared to 11% of the MCCR group (p = 0.03); 31% discontinued sulfonylureas in the LCK group, compared to 5% in the MCCR group (p = 0.05). The LCK group lost 5.5 kg vs. 2.6 kg lost in MCCR group (p = 0.09). Our results suggest that a very low carbohydrate diet coupled with skills to promote behavior change may improve glycemic control in type 2 diabetes while allowing decreases in diabetes medications. This clinical trial was registered with ClinicalTrials.gov, number NCT01713764.