Type 1 Diabetes Management Using a Very Low Carbohydrate Versus Standard Diet

Boston Children's Hospital32 enrolled

Overview

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.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

SUPPORTIVE_CARE

Masking

NONE

Enrollment

Interventions

very low carbohydrate dietOTHER

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.

standard carbohydrate dietOTHER

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.

Eligibility

Sex: ALLMin age: 18 YearsMax age: 40 Years

Medical Language ↔ Plain English

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 * For participants who undergo MRI: 1. Standard MRI exclusion criteria 2. Irregular menses 3. 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)

Outcomes

Primary Outcomes

Hemoglobin A1C change

HbA1C change from baseline at 12 weeks will be compared between the 2 interventions

Time frame: 12 weeks - baseline

Secondary Outcomes

total daily insulin dose

average daily insulin dose over 1 week will be calculated

Time frame: week 0 and 12

percent time spent in the glycemic target range of 70-140 mg/dl