Current Environment:


Despite major technological advances, management of type one diabetes mellitus (T1D) remains suboptimal, putting millions of people at risk for immediate and long-term complications. After meals, a mismatch between carbohydrate absorption rate and insulin action typically leads to alternating periods of hyper- and hypoglycemia. A conceptually promising approach to control both problems is dietary carbohydrate restriction to reduce postprandial blood glucose changes and insulin needs. In a prior survey study, the investigators documented exceptional glycemic control (HbA1c 5.67%) and low acute complication rates among 316 children and adults with T1D consuming a very-low-carbohydrate diet. To test the feasibility of this approach, the investigators will conduct a randomized-controlled feeding study involving 32 adults and adolescents with T1D. Participants will be randomized to receive a very low carbohydrate vs. standard carbohydrate diet. Participants will be in the study for 12 weeks and receive all their meals by meal delivery.They will share continuous glucose monitoring data with the study team and be in close communication to adjust insulin doses as needed. All participants will have a screening visit, an individual or group education session, and 3 study visits to evaluate diabetes control and metabolic health. Some of these visits will have a fasting blood draw. Two of the visits will also comprise additional metabolic studies to assess glucagon response and brain function during hypoglycemia by magnetic resonance imaging (MRI). Participants will have IV catheters placed and receive IV insulin to drop blood glucose levels to 50 mg/dl for up to 30 minutes. The primary outcome will be HbA1c change from baseline. Secondary outcomes include detailed measures of glycemic variability, metabolic health, and quality of life.



Recruitment Status


Eligibility Criteria

Inclusion Criteria:

Males and females with T1D for at least 1 year
Age 18 to 40 years
Tanner stage ≥ IV
BMI 18.5-35 kg/m2
Stable glycemic control (HbA1c 6.5-9%)
Use of a continuous glucose monitor (CGM)
Use of an insulin pump
Attendance of at least 1 diabetes care visit over the past 12 months (including virtual)

Exclusion Criteria:

Ketoacidosis or severe hypoglycemia with seizure or coma in the past 6 months
Dietary restrictions or intolerances that are incompatible with the planned food deliveries, e.g. celiac disease, gastroparesis, certain food allergies
Following a weight-loss or otherwise restrictive diet
Vigorous exercise >2 hours on >3 days a week
History of an eating disorder or at risk for eating disorder, assessed by the Eating Disorders Diagnostic Scale (EDDS)
Major medical illness or use of medications other than insulin and metformin that could interfere with metabolic or glycemic variables
Significant psychiatric illness
Smoking, use of recreational drugs, or excessive alcohol consumption
Pregnancy or breastfeeding

For participants who undergo MRI:

Standard MRI exclusion criteria
Irregular menses
Use of psychotropic medication other than SSRIs or other mild antidepressant or anxiety medications (unless these medications are safe to be held for several days to allow for the acquisition of MRI data)


Intervention Type

Intervention Name


very low carbohydrate diet


standard carbohydrate diet


Not Applicable



Min Age

18 Years

Max Age

40 Years

Download Date

July 3, 2023

Principal Investigator

Belinda Lennerz

Primary Contact Information

Belinda Lennerz, MD PhD


Svetlana Azova, MD


For more information on this trial, visit


For more information and to contact the study team:

Type 1 Diabetes Management Using a Very Low Carbohydrate Versus Standard Diet NCT03710928 Belinda Lennerz, MD PhD 8572183896 Svetlana Azova, MD 6179196675