Effect of Simulated Weight Loss on the Energy Cost of Locomotion in Overweight or Obese Adolescents

NCT07155746 | Not Yet Recruiting

• 2 other identifiers: RIPH2_GADEA_DELOAD2025-A01209-40
• Study Type: interventional
• Target: 20
• Locations: 0 countries
• Sites: N/A

Brief Summary

Current literature suggests that part of the energy response to weight loss is not due to changes in fat mass and lean mass, but rather to a homeostatic adaptation aimed at limiting or even preventing weight loss and preserving individuals' energy reserves, an adaptation known as "adaptive thermogenesis". This phenomenon calls for a closer look at the respective contributions of metabolic and mechanical changes induced by weight variations, with greater consideration given to the recently proposed hypothesis of dual regulation of homeostatic energy balance involving both leptin-dependent and "gravitostatic" pathways . While leptin-dependent regulation of body weight has been described and reinforced several times since the 1950s, the gravitostatic conception of this regulation is more recent and hypothesizes that terrestrial animals use gravity to regulate their body weight through receptors and pathways that have not yet been identified. This regulation would involve adaptations in energy consumption based on body weight when working against gravity, involving weight detection by osteocytes in weight-bearing bones, and leading to feedback regulation of energy metabolism and body weight . Preclinical and clinical studies conducted on rodents and human participants have shown a reduction in body weight after several weeks of mechanical overload (simulating weight gain), explained by adaptations in their food intake and energy metabolism , adaptations suggested to be particularly due to the regulation of muscle mass. Interestingly, preliminary results from this group highlight specific post-weight loss energy adaptations to such simulated weight regain in adolescents with obesity, suggesting the establishment of specific mechanisms promoting weight regain. Indeed, after weight loss, energy metabolism during locomotion was explored with and without simulated weight regain, and interestingly, energy expenditure did not return to pre-weight loss values, as a potential means of preserving weight regain. More recently, the investigators team has been able to show that such mechanical simulation of weight gain in adolescents with obesity but stable weight does not lead to an increase in their energy expenditure during locomotion, further reinforcing a susceptibility to not activating energy defense mechanisms against this weight gain.Overall, these results suggest the presence of mechanisms for preserving body mass by conserving energy stores as a compensatory defense system against weight loss, while highlighting the absence of activation of these mechanisms in the context of simulated weight gain. Indeed, while the compensatory mechanisms implicated in response to weight fluctuations have thus far been nutritional in nature, these energy adaptations, if confirmed, would suggest an upstream activation mechanism, particularly as a tonic signal for homeostatic control. It seems necessary to study in greater depth the energy adaptations to weight variations in young people with obesity, both metabolic and mechanical, in order to better understand the control of their energy balance and the mechanisms involved, which corresponds to the objectives of this project. The objective of this project is therefore to study energy adaptations (energy cost and use of energy substrates) to simulated weight loss during incremental walking exercise. Adolescents with obesity will perform a walking exercise on an AlterG (anti-gravity) treadmill, first without and then with a simulated weight loss that places them in the overweight or normal weight category.

Conditions

Obesity and Overweight

Outcome Measures

Primary Outcomes (1)

• Energy expenditure during incremental walking exercise measured by portable calorimetry

  Energy expenditure will be assessed during walking exercise using portable indirect calorimetry (MetaMax, Inc.). Indirect calorimetry is one of the classic methods for measuring resting energy expenditure. The contribution of lipid and carbohydrate oxidation will be calculated indirectly by monitoring oxygen consumption and CO2 output according to double unknown equations, assuming that protein oxidation is stable and around 15%.

  3 Months

Secondary Outcomes (2)

• The use of energy substrates during incremental walking exercise

  3 months

• Perception of effort during incremental walking exercise (Borg scale)

  3 months

Study Arms (1)

Adolescents aged 12 to 16 with obesity defined as a BMI above the 97th percentile

OTHER

3 different walking exercises

Other: Incremental walking exercise on an AlterG treadmill (anti-gravity)

Interventions

Incremental walking exercise on an AlterG treadmill (anti-gravity) OTHER

One visit with their current weight (BW) One visit with simulated weight loss in adolescents to determine their normal weight (NW-SBW) One visit with simulated weight loss in adolescents to determine their overweight status (OW-SBW).

Adolescents aged 12 to 16 with obesity defined as a BMI above the 97th percentile

Eligibility Criteria

• Age: 12 Years - 16 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Child (0-17)

You may qualify if:

• Adolescents aged 12 to 16 (inclusive), at Tanner stage 3-5, with obesity defined as a body mass index (BMI) above the 97th percentile according to national growth charts.
• No regular consumption of tobacco or alcohol,
• No diet (no calorie restriction, no specific diet such as a normal-calorie diet enriched with protein, vegetarian, or other),
• Adolescents affiliated with the social security system or equivalent,
• Adolescent who has been informed and has given written consent to participate in the study,
• Signed consent of both holders of parental authority (or one in the event of death, major incapacity, or withdrawal of parental authority).

You may not qualify if:

• Refusal to participate in the study,
• Refusal of consent by parents or guardians,
• Participation in regular and intense physical and sporting activities (no more than 150 minutes of moderate structured activity per week (according to WHO recommendations),
• Medical or surgical history deemed by the investigator to be incompatible with the study,
• Presence of diabetes or any other condition limiting the application of either strategy being tested,
• Taking medications that may interfere with the study results.
• Adolescents with cardiovascular problems, i.e., subjects with a history of cardiovascular and/or neurovascular disease, as well as subjects with cardiovascular and/or neurovascular risk factors (excluding obesity/overweight).
• Surgery in the previous 3 months,
• Adolescents who are currently excluded from another study,
• Pregnant or breastfeeding adolescents,
• Adolescents under guardianship/curatorship or legal protection,
• Parents under guardianship/curatorship or legal protection.

Sponsors & Collaborators

• Centre Hospitalier Emile Roux: lead

MeSH Terms

Conditions

Obesity; Overweight

Condition Hierarchy (Ancestors)

Overnutrition; Nutrition Disorders; Nutritional and Metabolic Diseases; Body Weight; Signs and Symptoms; Pathological Conditions, Signs and Symptoms

Study Officials

• David THIVEL Director of AME2P Laboratory - CLERMONT-FERRAND University

  Laboratoire des Adaptations Métaboliques à l'Exercice en conditions Physiologiques et Pathologiques

  PRINCIPAL INVESTIGATOR

Central Study Contacts

David THIVEL Director of AME2P Laboratory - CLERMONT-FERRAND University

CONTACT

+ 33 04 73 40 76 79; David.thivel@uca.fr

Sandra COURNIER Centre Hospitalier Emile ROUX

CONTACT

+33 04 71 04 34 20; sandra.cournier@ch-lepuy.fr

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NA
• Masking: NONE
• Purpose: OTHER
• Intervention Model: SINGLE GROUP
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: August 19, 2025
• First Posted: September 4, 2025
• Study Start: September 12, 2025
• Primary Completion (Estimated): February 28, 2027
• Study Completion (Estimated): May 31, 2027
• Last Updated: September 19, 2025

Record last verified: 2025-09