Sleep plays a crucial role in energy balance, alongside diet and physical activity. Research has linked poor sleep quality and short sleep duration to obesity and cardiometabolic risk, such as insulin resistance and hypertension. The nature of this association is complex, and several mechanims have been suggested.

Scientific evidence suggests that sleep interventions may provide additional benefits in optimizing the effectiveness of overweight/obesity treatment in pediatric populations. Although some studies have explored this hypothesis, methodological heterogeneity hampers clear interpretation of the results.

The main goal of this clinical trial is is to evaluate the efficacy of a sleep behavioral intervention, combined with standard obesity treatment, in reducing adiposity (measured by BMI z-score, fat mass percentage, or fat-free mass index) in adolescents with overweight or obesity.

This randomized controlled trial will compare a control group receiving treatment as usual (or standard obesity treatment) with an intervention group receiving treatment as usual plus a sleep behavioral intervention.

Participants will be randomized into two groups: intervention and control. Throughout the study period, all medical consultations will include standard interventions focused on nutrition, physical activity/sedentary behavior, and other lifestyle factors. The sleep-focused intervention will be delivered by psychologists.

Participants will attend clinic visits every two months during the 6-month intervention period, and every three months during the subsequent 6-month follow-up period.

A randomized controlled trial (open-label, behavioral intervention) will be conducted at ULS Cova da Beira and Hospital CUF Porto, enrolling 126 adolescents (ages 13-17) diagnosed with overweight or obesity and poor sleep quality. Participants will be randomized into two groups: the intervention group (sleep behavioral intervention plus treatment as usual) and the control group (treatment as usual).

In addition to the primary aim, the researchers will evaluate several secondary outcomes, including the efficacy of the intervention in relation to: cardiometabolic risk, sleep patterns, eating patterns, physical activity level, emotional well-being/self-compassion, quality of life, leptin and ghrelin levels, and tryptophan and melatonin metabolism.

Throughout the study period, all medical consultations will include standard multicomponent behavioral intervention. The sleep behavioral intervention will be conducted by psychologists.

The intervention consists of seven cognitive-behavioral therapy (CBT) sessions over six months, focusing on sleep hygiene, self-monitoring, stimulus control, cognitive therapy, and relaxation techniques.

Data collection and analysis will include objective sleep assessment using actigraphy and a level 3 ambulatory sleep study. Blood samples will be collected at baseline, six months, and twelve months to analyze metabolic markers. From the samples collected at months 0 and 6, a portion will be appropriately stored for additional analysis at an external facility to quantify leptin, ghrelin, and tryptophan pathway metabolites.

Anthropometric and clinical assessments will include measurements of body mass index (BMI), waist circumference, body composition, and blood pressure. Validated questionnaires will be used to evaluate sleep patterns, eating behaviors, physical activity, quality of life, emotional well-being, and self-compassion.

It is anticipated that the sleep behavioral intervention combined with standard treatment will be more effective than standard treatment alone not only in reducing adiposity, but also in improving cardiometabolic risk, sleep patterns, eating patterns, physical activity, emotional well-being, self-compassion, and in regulating hormonal and metabolic pathways including ghrelin, leptin, and the tryptophan-melatonin axis, as outlined in the study hypotheses

The study also aims to clarify the role of ghrelin and leptin levels, as well as the tryptophan pathway, in the interaction between sleep and obesity and in the effects of the intervention

Emotional well-being and self-compassion are expected to mediate the response to obesity intervention and the sleep-obesity relationship, potentially influencing or influenced by the tryptophan metabolic pathway, particularly serotonin levels.

By deepening the knowledge about the relationship between sleep and obesity, this research may contribute to optimize interventions for pediatric obesity, which would have an unequivocal positive impact.

Inclusion Criteria:

1. Informed consent from legal guardians and assent/consent from the adolescent;
2. Age between 13 and 17 years at the time of consent;
3. Diagnosis of overweight (BMI z-score > 1 and ≤ 2) or obesity (BMI z-score > 2), according to WHO criteria;
4. Sleep deprivation or poor sleep quality, based on the initial screening questionnaire.

Exclusion Criteria:

1. Secondary obesity (e.g., hypothalamic, genetic, or endocrine causes);
2. Comorbid psychiatric or neurological disorders (e.g., epilepsy, autism spectrum disorder) that affect sleep;
3. Current treatment with selective serotonin reuptake inhibitors (SSRIs) or other medications affecting sleep.

Individual participant data may be shared upon request, provided that all identifying information is removed to safeguard participant anonymity. This process upholds the confidentiality and privacy of participants, fully complying with ethical and legal standards for data protection.

June 2026 to June 2027

The data supporting the findings of this study will be available upon request from the corresponding author. Each request will be reviewed by the research team and the Ethics Committees that approved the study to ensure compliance with ethical standards.

Randomization is performed by a researcher not involved in data management.