Skip to main content
OpenTrials
Recruiting

NCT Number: NCT07667504

Dietary Approaches for the Management of Overweight and Obesity in Type 1 Diabetes

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.

Recruiting

Interested in participating?

Request Info

Key information

Conditions

Type 1 Diabetes (T1D) Autoimmune Diseases Body Weight Diabetes Mellitus Diabetes Mellitus, Type 1 Endocrine System Diseases Glucose Metabolism Disorders Immune System Diseases Metabolic Diseases Nutrition Disorders Nutritional and Metabolic Diseases Obesity Obesity & Overweight Overnutrition Overweight Pathological Conditions, Signs and Symptoms Signs and Symptoms

Age range

18 year–65 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Virgen de la Victoria University Hospital

Málaga, 29010, Spain

Location status: Recruiting

Location contact

Francisco J Tinahones, MD, PhD

PRINCIPAL_INVESTIGATOR

José Ignacio Martínez-Montoro, MD, PhD

PRINCIPAL_INVESTIGATOR

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

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.

Treatment and study plan

Moderate carbohydrate restriction

Behavioral

Participants will follow a diet with moderate carbohydrate restriction (25-30%), together with 25% caloric restriction

Early time-restricted eating

Behavioral

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

Standard calorie restriction

Behavioral

Participants will follow a standard diet with 25% caloric restriction

Primary outcomes

  1. Change in percent body weight

    Time frame: From baseline to 6 months

    Measured by a calibrated digital scale

Secondary outcomes

  1. Change in glycated hemoglobin

    Time frame: From baseline to 6 months

    Fasting blood samples. Glycated hemoglobin will be assessed by HPLC

  2. Change in continuous glucose monitoring (CGM) parameters

    Time frame: 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

  3. Change in absolute body weight (kg)

    Time frame: From baseline to 6 months

    Measured by a calibrated digital scale

  4. Change in body mass index (BMI)

    Time frame: From baseline to 6 months

    Calculated as kg/m2

  5. Change in anthropometric parameters

    Time frame: From baseline to 6 months

    Assessed by standard methods (waist circumference, hip circumference, waist-to-hip-ratio)

  6. Change in body composition (fat mass, fat-free mass)

    Time frame: From baseline to 6 months

    Assessed by air displacement plethysmography

  7. Change in systolic and diastolic blood pressure

    Time frame: From baseline to 6 months

    Measured by standard procedures

  8. Change in insulin dose

    Time frame: From baseline to 6 months

    Assessed by the recording of basal insulin dose, bolus insulin dose, total insulin dose (IU/day, IU/kg/day)

  9. Change in lipid profile

    Time frame: 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)

  10. Change in hepatic profile

    Time frame: From baseline to 6 months

    Fasting blood samples including several liver parameters (e.g., aspartate aminotransferase, alanine aminotransferase, gamma-glutamyl transferase)

  11. Change in estimated glucose disposal rate (eGDR)

    Time frame: From baseline to 6 months

    Insulin resistance will be calculated from waist circumference, hypertension status, and HbA1c

  12. Change in eating behavior

    Time frame: From baseline to 6 months

    Assessed by the Three-Factor Eating Questionnaire - Revised 18 items (TEFQ-18)

  13. Change in T1D-related distress

    Time frame: From baseline to 6 months

    Assessed by the Type1 Diabetes Distress Assessment System (T1-DDAS)

  14. Change in treatment satisfaction

    Time frame: From baseline to 6 months

    Assessed by the Diabetes Treatment Satisfaction Questionnaire, status version (DTSQs) and change version (DTSQc)

  15. Change in quality of life and general health

    Time frame: From baseline to 6 months

    Assessed by the EuroQol 5 dimensions 5 levels (EQ-5D-5L)

  16. Change in sleep quality

    Time frame: From baseline to 6 months

    Assessed by the Pittsburgh Sleep Quality Index (PSQI) and by accelorometry

  17. Change in ketonemia

    Time frame: From baseline to 6 months

    Measured by capillary blood β-hydroxybutyrate

  18. Change in physical activity

    Time frame: From baseline to 6 months

    Assessed by the International Physical Activity Questionnaire and by accelorometry

  19. Adverse events

    Time frame: From baseline to 6 months

    Assessed by systematic recording of adverse events throughout the study period

  20. Change in resting energy expenditure

    Time frame: From baseline to 6 months

    Assessed by indirect calorimetry

  21. Change in energy and nutrient intake

    Time frame: From baseline to 6 months

    Assessed by 24 h recalls

  22. Dietary adherence

    Time frame: From baseline to 6 months

    Assessed by 24 h recalls and adherence logs

Other outcomes

  1. Change in gut microbiota

    Time frame: From baseline to 6 months

    Gut microbiota composition and diversity, assessed by 16S rRNA

  2. Change in DNA methylation

    Time frame: From baseline to 6 months

    Measured by methylation array (Illumina)

  3. Change in inflammatory parameters

    Time frame: From baseline to 6 months

    Fasting blood samples, including several parameters (e.g., C-reactive protein, interleukin 6, interleukin IL-10, interleukin-1β, TNF-alpha)

  4. Change in adipokines and gastrointestinal hormones

    Time frame: From baseline to 6 months

    Fasting blood samples, including several parameters (e.g., leptin, adiponectin, GLP-1, GIP)

  5. Change in other cardiometabolic and renal biomarkers

    Time frame: From baseline to 6 months

    Fasting blood samples, including several parameters (e.g., apolipoprotein profile, homocysteine, N-terminal pro-B-type natriuretic peptide) and urinary albumin-to-creatinine ratio

  6. Change in phase angle

    Time frame: From baseline to 6 months

    Assessed by bioelectrical impedance analysis

  7. Change in ultrasound-assessed muscle and adipose tissue measurements (nutritional ultrasound)

    Time frame: From baseline to 6 months

    Assessed by ultrasound measurement of the rectus femoris muscle of the quadriceps, superficial and deep subcutaneous adipose tissue layers, and visceral adipose tissue

  8. Change in vibration-controlled transient elastography (VCTE) parameters

    Time frame: From baseline to 6 months

    Assessed by liver stiffness measurement (LSM) and controlled attenuation parameter (CAP)

  9. Change in sexual function

    Time frame: From baseline to 6 months

    Assessed by the International Index of Erectile Function (IIEF) for men and Female Sexual Function Measure (FSM-2) for women

Study contacts

Contact information is provided by the study sponsor or research team.

José Ignacio Martínez-Montoro, MD, PhD

CONTACT

[email protected]

+34 951032647

Sponsors and collaborators

Lead sponsor

Fundación Pública Andaluza para la Investigación de Málaga en Biomedicina y Salud

Other

Registry information

Official study title

Dietary Approaches for the Management of Overweight and Obesity in Type 1 Diabetes: The D1ANA Study

Acronym: D1ANA

Important dates

Study start
2026
Primary completion
2028
Study completion
2028
First posted
Jun 25, 2026
Registry last updated
Jul 15, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

Related clinical trials

Published trials that share one or more normalized conditions with this study.