Effects of Physical Exercise and a Nutritional Supplement on Body Composition, Metabolic Function, and Overall Health in Adults With a Metabolically Challenging Profile

The present project is designed as a longitudinal, randomized, controlled, parallel-group, triple-blind clinical trial, with a 12-week active intervention and pre- and post-intervention assessments.

The study will be conducted at a single center (single-center trial) and will include two parallel groups:

• Experimental group: multicomponent functional exercise + thermogenic and appetite-modulating nutritional supplement.
• Control group: multicomponent functional exercise + placebo supplement (identical in appearance, without active ingredient).

Randomization will be performed using balanced block allocation, stratified by sex and baseline body fat percentage, with a 1:1 allocation ratio.

The study will be triple-blind:

• Participants,
• The intervention and assessment team,
• And the statistician responsible for data analysis will remain unaware of group allocation (experimental or control).

The design corresponds to a comparative efficacy trial aimed at evaluating the additional effect of the nutritional supplement compared to placebo, while maintaining identical exercise programming and dietary control in both groups. This approach allows isolation of the specific impact of the supplement on body composition, metabolic function, functional capacity, and perceived health in adults with a metabolically challenged profile but without clinical obesity.

As is standard practice, participants will be informed that their allocation may correspond to either the placebo or experimental group, without disclosure of their actual assignment.

As appropriate in experimental studies, standardized collection of biological samples and psychometric and perceived health data will be conducted at pre- and post-intervention time points to quantify changes in these metrics and analyze them as dependent variables of the applied protocol.

Inclusion criteria

Individuals will be eligible to participate in the study if they meet all of the following criteria:

• Age: Between 50 and 65 years at the time of screening.
• Weight status (non-obese): Body mass index (BMI) between 25.0 and 29.9 kg/m² (overweight range, without clinical obesity).
• Metabolically challenged profile (non-obese): Presence of at least two of the following criteria, in addition to the specified BMI range:

A) Altered body composition (primary criterion): Body fat percentage ≥ 30% in women or ≥ 25% in men, assessed by DXA.

B) Borderline metabolic markers (one or more):

• Fasting glucose: 100-125 mg/dL
• Triglycerides: ≥ 150 mg/dL
• HDL cholesterol: < 50 mg/dL in women or < 40 mg/dL in men
• LDL cholesterol: ≥ 130 mg/dL

C) Sedentary lifestyle:

Low or very low physical activity level, defined as ≤ 600 MET·min/week according to the IPAQ questionnaire.

• Clinical and functional status:

• Clinically stable condition, without acute disease or recent decompensation.
• Ability to perform moderate-intensity exercise three times per week, according to medical assessment.
• Previous treatment and lifestyle:

• No participation in structured exercise programs (≥ 2 days/week) during the previous 6 months.
• No intensive hypocaloric diets or medical weight-loss treatments during the previous 3 months.
• Administrative and ethical aspects:

• Ability to understand study explanations and follow instructions.
• Signed informed consent prior to initiation of any study procedures.

Exclusion criteria

Individuals presenting any of the following conditions will be excluded from the study:

• Clinical obesity or anthropometric extremes:

• BMI ≥ 30.0 kg/m² (obesity).
• Any weight-related or clinical condition that, in the judgment of the principal investigator, contraindicates participation.
• Relevant or uncontrolled chronic diseases:

• Previous diagnosis of type 1 or type 2 diabetes mellitus.
• Moderate or severe cardiovascular disease (e.g., ischemic heart disease, heart failure, uncontrolled clinically significant arrhythmias).
• Moderate or severe renal, hepatic, or respiratory disease.
• Neurological or musculoskeletal disorders limiting or contraindicating the prescribed exercise program.
• Pharmacological treatments interfering with energy metabolism or body weight:

Current use (or use within the previous 3 months) of:

• Weight-loss medications or GLP-1 receptor agonists
• Systemic corticosteroids at moderate or high doses
• Thyroid hormones at non-replacement doses
• Anabolic agents or other drugs significantly affecting body composition
• Specific prior supplementation: Use of capsaicin, phenylcapsaicin, or other thermogenic or appetite-modulating supplements within the previous 3 months.
• Functional or cognitive limitations:

• Cognitive, psychiatric, or mental health disorders that may impair study comprehension or protocol adherence.
• Physical limitations preventing safe participation in exercise.
• Substance use:

• Alcohol consumption at levels considered high risk (> 20 g/day).
• Heavy smoking (> 10 cigarettes/day), unless deemed clinically stable by the investigator.
• Other exclusion criteria:

• Concurrent participation in another clinical trial or interventional study.
• Any other condition that, in the judgment of the principal investigator, may pose additional risk to the participant or significantly interfere with study outcomes.