Effects of Three Dietary Strategies on Body Composition and Metabolic Health in Adults With Overweight or Obesity

NCT07314177 | Completed DMC

• 2 other identifiers: PI24/171CEICA-13/2024-PI24-171
• Study Type: interventional
• Target: 45
• Locations: 1 country
• Sites: 1

Brief Summary

This study aims to compare the effects of three dietary interventions-a traditional Mediterranean diet, a Mediterranean low-carbohydrate diet, and a high-protein diet-on body composition, metabolic health markers, and metabolic syndrome remission in adults with overweight or obesity. A total of 45 participants will be randomly assigned to one of the three diets for 12 weeks, with regular follow-up by dietitians. Measurements will include weight, body fat, muscle mass, waist and hip circumference, blood pressure, and blood tests to assess glucose, cholesterol, inflammation, and other metabolic parameters. The findings will help determine whether one dietary pattern is more effective than others in improving short-term health outcomes in this population.

Conditions

Obesity &Amp; Overweight; Metabolic Syndrome (MetS); Cardiometabolic Risk Factors; Overweight (BMI > 25)

Keywords

Randomized controlled trial; Mediterranean diet; Low-carbohydrate diet; High-protein diet; Dietary intervention; Metabolic health

Outcome Measures

Primary Outcomes (1)

• Change in Body Mass Index (BMI, kg/m²) assessed by weight (Tanita MC-780MA bioimpedance scale) and height (Seca stadiometer) from baseline to 12 weeks

  BMI will be calculated as weight (kg) divided by height (m²). Weight will be measured without shoes using a Tanita MC-780MA multi-frequency bioelectrical impedance analyzer, and height will be measured using a calibrated Seca wall-mounted stadiometer.

  Baseline and week 12

Secondary Outcomes (8)

• Change in Fat Mass Percentage (%) assessed by Tanita MC-780MA bioelectrical impedance analyzer from baseline to 12 weeks

  Baseline and week 12

• Change in Fat-Free Mass Percentage (%) assessed by Tanita MC-780MA bioelectrical impedance analyzer from baseline to 12 weeks

  Baseline and week 12

• Change in Metabolic Syndrome Status (yes/no) defined by IDF criteria from baseline to 12 weeks

  Baseline and week 12

• Change in glycated hemoglobin (HbA1c, %) from baseline to 12 weeks

  Baseline and week 12

• Change in serum total cholesterol, LDL cholesterol, HDL cholesterol, and triglycerides (mg/dL) from baseline to 12 weeks

  Baseline and week 12

Study Arms (3)

Arm 1: Mediterranean Diet

EXPERIMENTAL

Participants assigned to this arm will follow a traditional Mediterranean diet providing approximately 55% of total energy from carbohydrates, 15% from protein, and 30% from fats. The diet emphasizes whole grains, fruits, vegetables, legumes, nuts, olive oil as the primary fat source, moderate fish and poultry intake, and limited consumption of red and processed meats, sweets, and sugary beverages. The prescribed energy intake represents a 20-25% caloric deficit based on individual estimated requirements. Participants receive personalized meal plans, nutritional education, and biweekly follow-up by a registered dietitian.

Other: Mediterranean Diet

Arm 2: Mediterranean Low-Carbohydrate Diet

EXPERIMENTAL

Participants assigned to this arm will follow a Mediterranean-style diet with a reduced carbohydrate content, providing approximately 40% of total energy from carbohydrates, 25% from protein, and 35% from fats. The diet retains the core principles of the Mediterranean pattern, emphasizing vegetables, fruits, legumes, nuts, fish, and olive oil, while limiting bread, pasta, rice, and other high-carbohydrate foods. Energy intake is individualized to achieve a 20-25% caloric deficit. Participants receive personalized meal plans, nutritional education, and biweekly follow-up by a registered dietitian.

Other: Mediterranean Low-Carbohydrate Diet

Arm 3: High-Protein Diet

EXPERIMENTAL

Participants assigned to this arm will follow a high-protein diet providing approximately 30% of total energy from carbohydrates, 40% from protein, and 30% from fats. Protein sources include lean meats, poultry, fish, eggs, and low-fat dairy products, combined with vegetables, nuts, and healthy fats such as olive oil. Refined carbohydrates and added sugars are limited. Energy intake is individualized to achieve a 20-25% caloric deficit. Participants receive personalized meal plans, nutritional education, and biweekly follow-up by a registered dietitian.

Other: High-Protein Diet

Interventions

Mediterranean Diet OTHER

A traditional Mediterranean diet providing approximately 55% of total energy from carbohydrates, 15% from protein, and 30% from fats. Emphasizes whole grains, vegetables, fruits, legumes, nuts, olive oil, moderate fish and poultry, and limited red meat, processed foods, and added sugars. Energy intake adjusted to achieve a 20-25% caloric deficit.

Arm 1: Mediterranean Diet

Mediterranean Low-Carbohydrate Diet OTHER

A Mediterranean-style diet with reduced carbohydrate content (40% of total energy from carbohydrates, 25% from protein, and 35% from fats). Retains core Mediterranean foods while limiting bread, pasta, rice, and other high-carb foods. Energy intake adjusted to achieve a 20-25% caloric deficit.

Arm 2: Mediterranean Low-Carbohydrate Diet

High-Protein Diet OTHER

A high-protein dietary pattern providing approximately 30% of total energy from carbohydrates, 40% from protein, and 30% from fats. Includes lean meats, poultry, fish, eggs, low-fat dairy, vegetables, nuts, and olive oil, with limited refined carbs and added sugars. Energy intake adjusted to achieve a 20-25% caloric deficit.

Arm 3: High-Protein Diet

Eligibility Criteria

• Age: 20 Years - 70 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Adults aged 20-70 years
• Body mass index (BMI) ≥ 25 kg/m² (overweight or obesity)
• Stable body weight (± 2 kg) in the last 3 months prior to screening
• Willingness to follow one of the prescribed dietary interventions for 12 weeks
• Ability to attend scheduled follow-up visits and complete study assessments
• Provided written informed consent prior to study participation

You may not qualify if:

• Diagnosis of type 1 diabetes, cardiovascular disease, cancer, chronic kidney disease, liver disease, or other serious chronic conditions that could interfere with the intervention
• Pregnancy or breastfeeding
• Current participation in another clinical trial
• History of bariatric surgery or weight-loss program within the past 6 months
• Use of medications known to affect body weight, metabolism, or appetite (e.g., glucocorticoids, weight-loss drugs, antipsychotics)
• Any food allergy or intolerance that would preclude adherence to the assigned diet
• Alcohol or substance abuse
• Any condition or circumstance that, in the opinion of the investigators, would make the participant unsuitable for the study

Sponsors & Collaborators

• Consorcio Centro de Investigación Biomédica en Red (CIBER): lead

Study Sites (1)

Edificio SAI

Zaragoza, Spain

Location

MeSH Terms

Conditions

Overweight; Obesity; Metabolic Syndrome

Interventions

Diet, Mediterranean; Diet, High-Protein

Condition Hierarchy (Ancestors)

Overnutrition; Nutrition Disorders; Nutritional and Metabolic Diseases; Body Weight; Signs and Symptoms; Pathological Conditions, Signs and Symptoms; Insulin Resistance; Hyperinsulinism; Glucose Metabolism Disorders; Metabolic Diseases

Intervention Hierarchy (Ancestors)

Diet, Plant-Based; Diet Therapy; Nutrition Therapy; Therapeutics; Diet; Nutritional Physiological Phenomena; Diet, Food, and Nutrition; Physiological Phenomena

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: NONE
• Purpose: OTHER
• Intervention Model: PARALLEL
• Sponsor Type: OTHER GOV
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: August 28, 2025
• First Posted: January 2, 2026
• Study Start: September 8, 2024
• Primary Completion: April 20, 2025
• Study Completion: June 25, 2025
• Last Updated: January 2, 2026

Record last verified: 2025-12

Data Sharing

• IPD Sharing: Will not share

Locations

ES (1)