Evaluation of a Nutritional Intervention With Dietary Supplements in People Who Have Recently Lost Weight: Effects on Body Composition, Emotional Health, and Gut Microbiota

The increasing use of GLP-1 receptor agonists and similar drugs has led to significant weight loss in many individuals; however, this is often followed by loss of lean mass, mood alterations, and gut microbiota imbalance. This study explores a nutritional supplementation strategy designed to support metabolic recovery and preserve physiological homeostasis in this population.

This 12-week randomized, double-blind, placebo-controlled clinical trial will include adults aged 25-60 years who have recently lost ≥5% of body weight due to pharmacological treatment or restrictive dietary patterns. Participants will be randomly assigned to one of two groups:

1. Experimental Group: Daily intake of a multi-component dietary supplement containing polyphenols and natural extracts with antioxidant and anti-inflammatory properties.
2. Placebo Group: Daily intake of an inert product with identical appearance, taste, and packaging.

All participants will continue their usual dietary and lifestyle habits. Compliance will be monitored through periodic visits and digital tracking.

Measurements will be taken at baseline and after 12 weeks, including:

* Body composition: fat mass, fat-free mass, and phase angle.
* Blood biomarkers: glucose, lipids, liver enzymes, and inflammatory markers.
* Psychological parameters: mood, anxiety, and quality of life scales.
* Gut microbiota: analysis of microbial diversity and composition from stool samples.

The expected outcome is that the supplement will mitigate lean mass loss, improve emotional balance, and restore microbiota diversity after significant weight reduction. Results from this study may contribute to developing safe and effective strategies for post-weight-loss management and metabolic health maintenance.

• Metabolaid®-based nutraceutical formulation (Dietary supplement): A 12-week supplementation with Metabolaid® to assess changes in body composition, emotional health, and gut microbiota after weight loss.
• Placebo capsules (Dietary supplement): A 12-week placebo supplementation with capsules identical in appearance to the experimental product, to evaluate differences in body composition, gut microbiota, and emotional parameters.

Primary outcomes

• Change in Fat Mass (%) [Baseline and Week 12]: To evaluate changes in total fat mass percentage after the 12-week intervention, assessed by bioimpedance analysis (BIODY XPERT ZM).

Secondary outcomes

• Change in Lean Mass (%) [Baseline and Week 12]: To evaluate changes in total lean body mass percentage after the 12-week intervention, measured by bioimpedance analysis.
• Change in Visceral Fat Level [Baseline and Week 12]: To assess differences in visceral adiposity index obtained from bioimpedance measurements before and after supplementation.
• Change in Body Weight (kg) [Baseline and Week 12]: To evaluate changes in body weight following the 12-week supplementation period.
• Change in BMI (kg/m²) [Baseline and Week 12]: To assess changes in body mass index calculated as weight (kg) divided by height squared (m²).
• Change in Waist Circumference (cm) [Baseline and Week 12]: To measure changes in abdominal circumference as an indicator of central adiposity.
• Change in Hip Circumference (cm) [Baseline and Week 12]: To record changes in hip circumference to calculate waist-to-hip ratio.
• Change in Gut Microbiota Diversity [Baseline and Week 12]: To evaluate changes in microbial alpha and beta diversity using 16S rRNA sequencing of stool samples.
• Change in Abundance of Key Gut Microbial Taxa [Baseline and Week 12]: To analyze specific bacterial taxa abundance associated with metabolic health before and after the intervention.
• Change in Appetite Score (VAS) [Baseline and Week 12]: Description: Appetite perception will be evaluated using a Visual Analogue Scale (VAS) consisting of a 100-mm horizontal line, where 0 represents "no appetite at all" and 100 represents "extremely high appetite." Participants will mark their perceived level of appetite on the line, and the score will be measured in millimeters from the left end. Range: 0-100 mm. Interpretation: Higher scores indicate greater appetite perception.
• Change in Satiety Score (VAS) [Baseline and Week 12]: Description: Perceived fullness or satiety will be evaluated using a Visual Analogue Scale (VAS) consisting of a 100-mm horizontal line, where 0 represents "not at all full" and 100 represents "extremely full." Participants will indicate their perceived level of satiety on the line, and the score will be measured in millimeters from the left end. Range: 0-100 mm. Interpretation: Higher scores indicate greater perceived satiety.
• Change in Physical Activity Level (IPAQ Total Score) [Baseline and Week 12]: Description: Physical activity levels will be assessed using the International Physical Activity Questionnaire - Short Form (IPAQ-SF), which records activity performed over the previous 7 days. The questionnaire includes 7 items covering walking, moderate, and vigorous activities. The total score is expressed in MET-minutes per week and categorized into low, moderate, or high activity levels. Range: 0 to unlimited MET-min/week. Interpretation: Higher scores indicate greater physical activity levels.
• Change in Total Energy Intake (kcal/day) [Baseline and Week 12]: To quantify changes in daily energy consumption from dietary recalls.
• Change in Macronutrient Distribution (%) [Baseline and Week 12]: To evaluate changes in carbohydrate, protein, and fat intake percentages.
• Change in Fasting Glucose (mg/dL) [Baseline and Week 12]: To assess changes in fasting blood glucose levels as a metabolic indicator.
• Change in Fasting Insulin (µU/mL) [Baseline and Week 12]: To measure insulin levels to assess metabolic response to supplementation.
• Change in Total Cholesterol (mg/dL) [Baseline and Week 12]: To measure total cholesterol concentration in fasting blood samples.
• Change in HDL Cholesterol (mg/dL) [Baseline and Week 12]: To assess HDL cholesterol changes after supplementation.
• Change in LDL Cholesterol (mg/dL) [Baseline and Week 12]: To evaluate low-density lipoprotein cholesterol levels before and after intervention.
• Change in Triglycerides (mg/dL) [Baseline and Week 12]: To determine the impact of supplementation on triglyceride concentrations.
• Change in C-Reactive Protein (mg/L) [Baseline and Week 12]: To assess systemic inflammation through C-reactive protein levels.
• Change in Interleukin-6 (pg/mL) [Baseline and Week 12]: To evaluate inflammatory status through IL-6 concentrations
• Change in TNF-alpha (pg/mL) [Baseline and Week 12]: To measure tumor necrosis factor-alpha as an additional inflammatory marker

Sex: All, ages: 25 Years to 60 Years

Inclusion Criteria:

* Adults aged 25 to 60 years.
* Documented unintentional or pharmacologically induced weight loss of ≥5% during the previous 3 months.
* Stable body weight (±2 kg variation) during the 2 weeks prior to enrollment.
* Completion or discontinuation of GLP-1 receptor agonist or other pharmacological weight-loss therapy within the last 3 months.
* Willingness to maintain habitual dietary and physical activity habits throughout the study.
* Ability to provide written informed consent and comply with all study procedures.

Exclusion Criteria:

* Current or recent use (within 3 months) of antibiotics, probiotics, or prebiotic supplements.
* Active gastrointestinal disorders (e.g., inflammatory bowel disease, celiac disease, chronic diarrhea, or severe constipation).
* Diagnosis of diabetes mellitus, cardiovascular disease, cancer, liver, or kidney dysfunction.
* Pregnancy, breastfeeding, or intention to become pregnant during the study period.
* Psychiatric disorders or use of medications affecting mood or appetite.
* Participation in another clinical trial during the previous 3 months.
* Any condition that, in the investigator's opinion, could interfere with study participation or interpretation of results.