Type 1 Diabetes Management Using a Very Low Carbohydrate Versus Standard Diet
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ClinicalTrials.gov Identifier: NCT03710928 |
Recruitment Status :
Recruiting
First Posted : October 18, 2018
Last Update Posted : March 21, 2022
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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.
Condition or disease | Intervention/treatment | Phase |
---|---|---|
Type1diabetes | Other: very low carbohydrate diet Other: standard carbohydrate diet | Not Applicable |
Study Type : | Interventional (Clinical Trial) |
Estimated Enrollment : | 32 participants |
Allocation: | Randomized |
Intervention Model: | Parallel Assignment |
Intervention Model Description: | randomized controlled trial, 12-week feeding study |
Masking: | None (Open Label) |
Primary Purpose: | Supportive Care |
Official Title: | Type 1 Diabetes Management Using a Very Low Carbohydrate Versus Standard Diet |
Actual Study Start Date : | January 3, 2020 |
Estimated Primary Completion Date : | December 31, 2022 |
Estimated Study Completion Date : | December 31, 2022 |

Arm | Intervention/treatment |
---|---|
Experimental: very low carbohydrate diet
Dietary Intervention, food delivery
|
Other: very low carbohydrate diet
All meals will be delivered and participants will consume study foods exclusively. Participants will receive a fiber supplement as needed with each meal to support digestive health, and a daily multi-vitamin, magnesium and omega-three supplement to ascertain micronutrient sufficiency. Participants will be weighed at each study visit and the diet plan will be adjusted for satiety and weight-maintenance. The diet composition will be as follows: 5% carbohydrate, 70% fat, 20% protein. |
Active Comparator: standard diet
Dietary Intervention, food delivery
|
Other: standard carbohydrate diet
All meals will be delivered and participants will consume study foods exclusively. Participants will receive a daily multi-vitamin and omega-3 supplement to ascertain micronutrient sufficiency. Participants will be weighed at each study visit and the diet plan will be adjusted for satiety and weight-maintenance. The diet composition will be as follows: 50% carbohydrate, 30% fat, 20% protein. |
- Hemoglobin A1C change [ Time Frame: 12 weeks - baseline ]HbA1C change from baseline at 12 weeks will be compared between the 2 interventions
- total daily insulin dose [ Time Frame: week 0 and 12 ]average daily insulin dose over 1 week will be calculated
- percent time spent in the glycemic target range of 70-140 mg/dl [ Time Frame: week 0 and 12 ]will be calculated from 1-week continuous glucose monitoring data
- percent time spent below the glycemic target of 70 mg/dl [ Time Frame: week 0 and 12 ]will be calculated from 1-week continuous glucose monitoring data
- percent time in hypoglycemia below 54 mg/dl [ Time Frame: week 0 and 12 ]will be calculated from 1-week continuous glucose monitoring data
- percent time spent above the glycemic target of 140 mg/dl [ Time Frame: week 0 and 12 ]will be calculated from 1-week continuous glucose monitoring data
- percent time spent in hyperglycemia [ Time Frame: week 0 and 12 ]will be calculated from 1-week continuous glucose monitoring data
- blood glucose average [ Time Frame: week 0 and 12 ]will be calculated from 1-week continuous glucose monitoring data
- blood glucose standard deviation [ Time Frame: week 0 and 12 ]will be calculated from 1-week continuous glucose monitoring data
- Glycemic Variability Index, a measure for glycemic variability normalized to mean blood glucose level [ Time Frame: week 0 and 12 ]will be calculated by dividing blood glucose standard deviation by blood glucose average
- Mean Amplitude of Glycemic Excursions (MAGE), a measure for postprandial glycemic variability [ Time Frame: week 0 and 12 ]will be calculated by dividing blood glucose standard deviation by blood glucose average
- fasting total cholesterol [ Time Frame: week 0 and 12 ]from venous blood
- fasting high density lipoprotein cholesterol [ Time Frame: week 0 and 12 ]from venous blood
- fasting low density lipoprotein cholesterol [ Time Frame: week 0 and 12 ]from venous blood
- fasting triglycerides [ Time Frame: week 0 and 12 ]from venous blood
- fasting beta hydroxybutyrate [ Time Frame: weeks 0, 1, 2, 4, 6, 9, 12 ]from venous blood and/or point-of-care testing
- fasting high-sensitivity c-reactive protein [ Time Frame: week 0 and 12 ]from venous blood
- Self-reported quality of life assessed per self-report by The Problem Areas in Diabetes Scale (PAID) [ Time Frame: week 0, 6, and 12 ]The scores for each item are summed, then multiplied by 1.25 to generate a total score out of 100.
- Becks Depression Inventory II (BDI II) less suicidality [ Time Frame: week 0, 6, and 12 ]BDI-II less suicidality is a 20-item self-report inventory that measures assesses for presence and severity of depression depressive symptoms. Each item is scored between 0-3. Item scores are added up to a total score (max. 60) and reported.
- Yale Food Addiction Scale 2.0 (YFAS 2.0) [ Time Frame: week 0, 6, and 12 ]Assesses indicators of addictive-like eating.The YFAS includes two scoring options: 1) a "symptom count" that reflects the number of addiction-like criteria endorsed and 2) a dichotomous "diagnosis" that indicates whether a threshold of three or more "symptoms" plus clinically significant impairment or distress has been met. The diagnosis score will be calculated at baseline and used as an effect modifier. Symptom counts will be reported separately as a longitudinal measure.
- Highly Processed Food Withdrawal Scale (ProWS) [ Time Frame: Baseline, daily on days 1-7, then weekly; primary focus on change from baseline to day 7 ]Assesses withdrawal-type symptoms that may occur when individuals cut down on rewarding foods.

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Ages Eligible for Study: | 18 Years to 40 Years (Adult) |
Sexes Eligible for Study: | All |
Accepts Healthy Volunteers: | No |
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
- Anemia
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For participants who undergo MRI:
- Standard MRI exclusion criteria
- Irregular menses
- Use of psychotropic medication (unless these medications are safe to be held for several days to allow for the acquisition of MRI data)

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT03710928
Contact: Belinda Lennerz, MD PhD | 8572183896 | belinda.lennerz@childrens.harvard.edu | |
Contact: Svetlana Azova, MD | 6179196675 | svetlana.azova@childrens.harvard.edu |
United States, Massachusetts | |
Boston Children's Hospital | Recruiting |
Boston, Massachusetts, United States, 02115 | |
Contact: Belinda S Lennerz, MD PhD 857-218-3896 belinda.lennerz@childrens.harvard.edu | |
Contact: Svetlana Azova, MD 6179196675 svetlana.azova@childrens.harvard.edu |
Responsible Party: | Belinda Lennerz, Principal Investigator, Boston Children's Hospital |
ClinicalTrials.gov Identifier: | NCT03710928 |
Other Study ID Numbers: |
IRB-P00030039 |
First Posted: | October 18, 2018 Key Record Dates |
Last Update Posted: | March 21, 2022 |
Last Verified: | March 2022 |
Individual Participant Data (IPD) Sharing Statement: | |
Plan to Share IPD: | Undecided |
Studies a U.S. FDA-regulated Drug Product: | No |
Studies a U.S. FDA-regulated Device Product: | No |
very low carbohydrate diet nutrition ketogenic diet ketosis |
nutritional ketosis metabolism metabolic health |
Diabetes Mellitus Diabetes Mellitus, Type 1 Glucose Metabolism Disorders Metabolic Diseases |
Endocrine System Diseases Autoimmune Diseases Immune System Diseases |