Obesity & Overweight, Type 1 Diabetes (T1D)
Conditions
Brief summary
Although type 1 diabetes (T1D) has traditionally been considered a disease associated with a lean phenotype, it is estimated that up to 2 out of 3 people living with T1D are overweight or obese, factors linked to an increased risk of complications in these patients. The available evidence regarding nutritional strategies for weight loss in T1D is very limited, and clinical trials are needed to determine how to effectively and safely promote weight loss in this population. In recent years, low-carbohydrate diets and several intermittent fasting protocols have demonstrated efficacy in promoting weight loss both in patients with type 2 diabetes and in patients with obesity without diabetes. This study will evaluate the efficacy of moderate carbohydrate restriction, time-restricted eating, and standard calorie restriction for weight loss in adults with T1D and overweight/obesity.
Interventions
BEHAVIORALModerate carbohydrate restriction
Participants will follow a diet with moderate carbohydrate restriction (25-30%), together with 25% caloric restriction
BEHAVIORALEarly time-restricted eating
Participants will follow a standard diet with an 8-hour early eating window, starting no later than 10 a.m. (16-hour fast), together with 25% caloric restriction
BEHAVIORALStandard calorie restriction
Participants will follow a standard diet with 25% caloric restriction
Sponsors
Fundación Pública Andaluza para la Investigación de Málaga en Biomedicina y Salud
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
SINGLE (Outcomes Assessor)
Masking description
Outcome assessors and data analysts will be blinded to treatment allocation
Eligibility
Sex/Gender
ALL
Age
18 Years to 65 Years
Healthy volunteers
No
Inclusion criteria
* T1D treated with intensive insulin therapy (multiple daily insulin injections or continuous subcutaneous insulin infusion systems) * HbA1c 6.5-9% * BMI ≥ 25 and ≤ 45 kg/m2 * Active prescription and use of CGM * Active prescription for glucagon
Exclusion criteria
* Pregnancy, pregnancy planning, or breastfeeding * Forms of diabetes other than T1D, or T1D duration \< 1 year * Previous cardiovascular events (acute myocardial infarction or stroke), heart failure, unstable coronary artery disease, chronic kidney disease with estimated glomerular filtration rate ≤ 30 mL/min/m², cirrhosis, or presence of active cancer * Unstable diabetes, episodes of glycemic decompensation (diabetic ketoacidosis) or severe hypoglycemia (level 3) within the past year. * Planned change in treatment during the study (switching from multiple daily insulin injections to continuous insulin infusion, or vice versa) * Use of sodium-glucose cotransporter 2 inhibitors, glucagon-like peptide-1 (GLP-1) receptor agonists, GLP-1/GIP agonists, or other medications that may influence weight loss * Having experienced a change in body weight greater than 5% within the 3 months before screening * Following any form of diet prior to inclusion, carbohydrate restriction, or intermittent fasting * History of eating disorders or alcohol abuse * Inability to follow the dietary recommendations * Presence of other conditions that, in the investigator's judgment, may compromise participation in the study.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Change in percent body weight | From baseline to 6 months | Measured by a calibrated digital scale |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Change in glycated hemoglobin | From baseline to 6 months | Fasting blood samples. Glycated hemoglobin will be assessed by HPLC |
| Change in continuous glucose monitoring (CGM) parameters | From baseline to 6 months | Parameters measured by CGM, including time in range, time below range, mean glucose, standard deviation of glucose, coefficient of variation of glucose, time above range, time in tight range, glucose management indicator |
| Change in absolute body weight (kg) | From baseline to 6 months | Measured by a calibrated digital scale |
| Change in body mass index (BMI) | From baseline to 6 months | Calculated as kg/m2 |
| Change in anthropometric parameters | From baseline to 6 months | Assessed by standard methods (waist circumference, hip circumference, waist-to-hip-ratio) |
| Change in body composition (fat mass, fat-free mass) | From baseline to 6 months | Assessed by air displacement plethysmography |
| Change in systolic and diastolic blood pressure | From baseline to 6 months | Measured by standard procedures |
| Change in insulin dose | From baseline to 6 months | Assessed by the recording of basal insulin dose, bolus insulin dose, total insulin dose (IU/day, IU/kg/day) |
| Change in lipid profile | From baseline to 6 months | Fasting blood samples, including several lipid parameters (e.g., total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, triglycerides) |
| Change in hepatic profile | From baseline to 6 months | Fasting blood samples including several liver parameters (e.g., aspartate aminotransferase, alanine aminotransferase, gamma-glutamyl transferase) |
| Change in estimated glucose disposal rate (eGDR) | From baseline to 6 months | Insulin resistance will be calculated from waist circumference, hypertension status, and HbA1c |
| Change in eating behavior | From baseline to 6 months | Assessed by the Three-Factor Eating Questionnaire - Revised 18 items (TEFQ-18) |
| Change in T1D-related distress | From baseline to 6 months | Assessed by the Type1 Diabetes Distress Assessment System (T1-DDAS) |
| Change in treatment satisfaction | From baseline to 6 months | Assessed by the Diabetes Treatment Satisfaction Questionnaire, status version (DTSQs) and change version (DTSQc) |
| Change in quality of life and general health | From baseline to 6 months | Assessed by the EuroQol 5 dimensions 5 levels (EQ-5D-5L) |
| Change in sleep quality | From baseline to 6 months | Assessed by the Pittsburgh Sleep Quality Index (PSQI) and by accelorometry |
| Change in ketonemia | From baseline to 6 months | Measured by capillary blood β-hydroxybutyrate |
| Change in physical activity | From baseline to 6 months | Assessed by the International Physical Activity Questionnaire and by accelorometry |
| Adverse events | From baseline to 6 months | Assessed by systematic recording of adverse events throughout the study period |
| Change in resting energy expenditure | From baseline to 6 months | Assessed by indirect calorimetry |
| Change in energy and nutrient intake | From baseline to 6 months | Assessed by 24 h recalls |
| Dietary adherence | From baseline to 6 months | Assessed by 24 h recalls and adherence logs |
Countries
Spain
Contacts
CONTACTJosé Ignacio Martínez-Montoro, MD, PhD
PRINCIPAL_INVESTIGATORJosé Ignacio Martínez-Montoro, MD, PhD
Virgen de la Victoria University Hospital, Málaga, Spain
PRINCIPAL_INVESTIGATORFrancisco J Tinahones, MD, PhD
Virgen de la Victoria University Hospital, Málaga, Spain
Outcome results
None listed