Overweight (BMI > 25), Obesity &Amp; Overweight, Metabolic Syndrome (MetS), Cardiometabolic Risk Factors
Conditions
Keywords
Randomized controlled trial, Mediterranean diet, Low-carbohydrate diet, High-protein diet, Dietary intervention, Metabolic health
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.
Detailed description
Detailed Description: This randomized, controlled, parallel-group pilot clinical trial will evaluate the effects of three different hypocaloric dietary strategies on body composition, metabolic markers, and metabolic syndrome remission in adults with overweight or obesity. Background and Rationale Overweight and obesity are highly prevalent in Europe and are associated with an increased risk of metabolic syndrome, cardiovascular disease, type 2 diabetes, and obesity-related cancers. Dietary interventions are a cornerstone in their management, but the optimal macronutrient composition for improving short-term metabolic outcomes remains unclear. This study investigates the comparative impact of a traditional Mediterranean diet, a Mediterranean low-carbohydrate diet, and a high-protein diet over a 12-week period. Study Design A total of 45 participants aged 18-65 years with a body mass index (BMI) ≥25 kg/m² will be recruited through online advertisements and primary care referrals. After eligibility screening and informed consent, participants will be randomly allocated (1:1:1) to one of the three dietary intervention arms. Intervention All diets will be hypocaloric, aiming for a 20-25% reduction in individual energy requirements, and will differ in macronutrient distribution: Mediterranean diet: 55% carbohydrates, 15% proteins, 30% fats. Mediterranean low-carbohydrate diet: 40% carbohydrates, 25% proteins, 35% fats. High-protein diet: 30% carbohydrates, 40% proteins, 30% fats. Participants will be followed biweekly by qualified dietitians through in-person or phone consultations. They will receive personalized meal plans, nutritional education, and support materials to enhance adherence. Assessments Anthropometric measures (BMI, fat mass, fat-free mass, waist and hip circumference) will be obtained at baseline and at 12 weeks using standardized protocols and validated equipment. Blood pressure will be measured with a calibrated automated device after a seated rest. Fasting blood samples will be collected in the morning for biochemical analyses, including glucose, HbA1c, insulin, lipid profile, uric acid, iron status, high-sensitivity C-reactive protein, fibrinogen, erythrocyte sedimentation rate, and liver enzymes. Outcomes The primary outcome is the change in BMI after 12 weeks. Secondary outcomes include changes in body composition, metabolic and inflammatory biomarkers, and the proportion of participants meeting the International Diabetes Federation (IDF) criteria for metabolic syndrome at baseline and post-intervention. Ethics and Dissemination The study protocol was approved by the Ethics Committee of Aragón (CEICA) (No. 13/2024) and will be conducted in accordance with the Declaration of Helsinki and current regulatory requirements. The findings will be disseminated through peer-reviewed publications and conference presentations.
Interventions
OTHERMediterranean Diet
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.
OTHERMediterranean Low-Carbohydrate Diet
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.
OTHERHigh-Protein Diet
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.
Sponsors
Consorcio Centro de Investigación Biomédica en Red (CIBER)
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
OTHER
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
20 Years to 70 Years
Healthy volunteers
No
Inclusion criteria
* 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
Exclusion criteria
* 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
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| 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 | Baseline and week 12 | 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. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Change in Fat-Free Mass Percentage (%) assessed by Tanita MC-780MA bioelectrical impedance analyzer from baseline to 12 weeks | Baseline and week 12 | Fat-free mass percentage will be estimated using multi-frequency segmental bioelectrical impedance analysis (Tanita MC-780MA). |
| Change in Metabolic Syndrome Status (yes/no) defined by IDF criteria from baseline to 12 weeks | Baseline and week 12 | Metabolic syndrome will be diagnosed according to the International Diabetes Federation (IDF) criteria, requiring ≥3 of the following: elevated waist circumference, elevated triglycerides, reduced HDL cholesterol, elevated blood pressure, or elevated fasting glucose. |
| Change in glycated hemoglobin (HbA1c, %) from baseline to 12 weeks | Baseline and week 12 | HbA1c levels will be measured in fasting venous blood samples using high-performance liquid chromatography (HPLC), following standardized laboratory procedures. |
| Change in Fat Mass Percentage (%) assessed by Tanita MC-780MA bioelectrical impedance analyzer from baseline to 12 weeks | Baseline and week 12 | Fat mass percentage will be estimated using multi-frequency segmental bioelectrical impedance analysis (Tanita MC-780MA). |
| Change in fasting glucose (mg/dL) from baseline to 12 weeks | Baseline and week 12 | Fasting glucose concentration will be measured in venous blood samples collected early in the morning under standardized fasting conditions. Glucose levels will be quantified using validated automated enzymatic assays in a certified clinical laboratory. |
| Change in high-sensitivity C-reactive protein (hs-CRP, mg/dL) from baseline to 12 weeks | Baseline and week 12 | Serum hs-CRP concentrations will be measured in fasting venous blood samples collected in the morning and analyzed using a standardized high-sensitivity immunoassay in a certified clinical laboratory. Values will be reported in mg/dL. |
| Change in serum uric acid (mg/dL) from baseline to 12 weeks | Baseline and week 12 | Serum uric acid will be measured by an enzymatic colorimetric method in a certified laboratory. Results will be reported in mg/dL. |
| Change in serum total cholesterol, LDL cholesterol, HDL cholesterol, and triglycerides (mg/dL) from baseline to 12 weeks | Baseline and week 12 | Serum lipids will be determined from fasting blood samples analyzed enzymatically in a certified laboratory. Results will be reported in mg/dL for each parameter. |
Countries
Spain
Outcome results
None listed