Effect of Low-calorie Diets With Different Macronutrient Composition and Macronutrient Distribution in Shift Workers With Prediabetes or Type 2 Diabetes and Overweight or Obesity.

Not Applicable

Recruiting

• Conditions: Type 2 Diabetes; Overweight or Obesity; PreDiabetes

• Registration Number: NCT06912555
• Lead Sponsor: Universidad de Zaragoza

Brief Summary

Background and Aims: Shift work, particularly involving night shifts, is associated with increased risk of metabolic disturbances such as type 2 diabetes mellitus (T2DM). Thus, it is important to explore mechanisms underlying this deleteroius effect and strategies that could prevent or mitigate it. The aim of the study is to investigate the effect of three low-calorie diets with different macronutrients composition and distribution along day on glucose metabolism and other health outcomes in overweight or obese shift workers with prediabetes or T2DM.

Methods: In this randomized controlled trial, 120 shift workers with a BMI \> 27.5 kg/m2 and diagnosed with prediabetes or T2DM will be recruited. The trial assesses three low-calorie diets effects on glucose metabolism, body composition, and health outcomes over 12 weeks. These diets include: A) high-protein dinner (60% of total daily protein), B) low-protein dinner (15% of total daily protein), and C) normoproteic diet.

Detailed Description

Not available

Study Timeline

• Study Start: 2024-09-01
• Status Verified: 2025-03
• Study First Submitted: 2025-03-24
• Study First Submitted QC: 2025-03-31
• Last Update Submitted: 2025-03-31
• Study First Posted: 2025-04-04
• Last Update Posted: 2025-04-04
• Primary Completion: 2025-11-30
• Study Completion: 2025-12-31

Recruitment & Eligibility

• Status: RECRUITING
• Sex: All
• Target Recruitment: 120

Inclusion Criteria

• Body mass index (BMI) ranging between 27.5 and 40 kg/m2.
• Presence of prediabetes (fasting glucose between 100-125 mg/dL and/or glycated hemoglobin between 5.7 and 6.4%) or type 2 diabetes mellitus (fasting glucose ≥ 126 mg/dL and/or glycated hemoglobin ≥ 6.5% and/or currently taking metformin), based on the criteria of the American Diabetes Association.
• Engaged in shift work, including night shifts, for at least 1 year and intending to maintain this schedule in the upcoming months.
• Provide written informed consent for voluntary participation in the study after reviewing the participant information sheet and addressing any resulting queries.

Exclusion Criteria

• Treatment with antidiabetic medications (oral or subcutaneous) or insulin in the last 2 months, except for stable use of metformin or Dipeptidyl peptidase 4 (DPP-4) inhibitors for a minimum of 6 months.
• Treatment with lipid-lowering agents in an unstable manner for at least 6 months prior to study entry.
• Regular consumption of functional foods such as phytosterols or red yeast rice, which have a significant effect on lipid or glucose metabolism, in an unstable manner for at least 6 months prior to study entry.
• Presence of other chronic conditions that are not well-controlled and could interfere with study outcomes, such as cardiovascular disease, renal disease, or liver disease.
• Presence of uncontrolled endocrine disorders, including hypothyroidism.
• Use of medications that could interfere with lipid and/or glucose metabolism, unless taken stably throughout the study.
• Consumption of sleep supplements, except for stable use for 6 months with the intention to continue stable use throughout the study.
• Presence of any laboratory abnormalities that could affect study results.
• Weight gain or loss of ≥ 5% in the last 3 months.
• Use of vitamin supplements in an unstable manner for at least 6 months prior to study entry.
• High intake of alcohol (> 30 g of ethanol) on a regular basis.
• Pregnancy or intention to become pregnant during the study.
• Severe illness of any kind with a life expectancy of less than 1 year or that, in the investigators' judgment, limits uniform dietary intake throughout the study.
• Any other circumstance that, in the investigators' judgment, would impede adequate adherence to the proposed nutritional intervention (e.g., frequent travel during the study, inability to attend visits due to personal or work-related circumstances, etc.).

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Primary Outcome Measures

Name	Time	Method
Glucose change.	After 3 months of intervention.	Glucose change assessed by difference in fasting glucose concentration (mg/dL and %) comparing 3 months visit with respect to baseline.
Insulin change.	After 3 months of intervention.	Insulin change assessed by difference in fasting insulin concentration (UI/mL and %) comparing 3 months visit with respect to baseline.
HOMA-IR change.	After 3 months of intervention.	HOMA-IR change assessed by difference in HOMA-IR concentration (absolute units and %) comparing 3 months visit with respect to baseline.
Body fat mass change.	After 3 months of intervention.	Body fat mass change assessed by difference in fat mass (%) comparing 3 months visit with respect to baseline.
Fat-free mass change.	After 3 months of intervention.	Fat-free mass change assessed by difference in fat free-mass (%) comparing 3 months visit with respect to baseline.
Visceral fat mass change.	After 3 months of intervention.	Visceral fat mass change assessed by difference in visceral fat mass (kg and %) comparing 3 months visit with respect to baseline.
Glycated hemoglobin change.	After 3 months of intervention.	Glycated change assessed by difference in glycated hemoglobin concentration (%) comparing 3 months visit with respect to baseline.

Secondary Outcome Measures

Name	Time	Method
Total cholesterol change.	After 3 months of intervention.	Total cholesterol change assessed by difference in fasting total cholesterol concentration (mg/dL and %) comparing 3 months visit with respect to baseline.
LDL cholesterol change.	After 3 months of intervention.	LDL cholesterol change assessed by difference in fasting LDL cholesterol concentration (mg/dL and %) comparing 3 months visit with respect to baseline.
HDL cholesterol change.	After 3 months of intervention.	HDL cholesterol change assessed by difference in fasting HDL cholesterol concentration (mg/dL and %) comparing 3 months visit with respect to baseline.
Triglycerides change.	After 3 months of intervention.	Triglycerides change assessed by difference in fasting Triglycerides concentration (mg/dL and %) comparing 3 months visit with respect to baseline.

Trial Locations

Locations (1)

Instituto de Investigación Sanitaria Aragón, Hospital Universitario Miguel Servet, Universidad de Zaragoza; 🇪🇸 Zaragoza, Spain