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NCT Number: NCT07402031

Predicting Weight Loss After Pharmacological or Surgical Treatment in Patients With Obesity

As with other nutritional strategies, the clinical response to bariatric surgery can be highly variable, with weight regain being a frequent occurrence. Recent evidence on anti-obesity medication indicate similar inter-individual variability in clinical response. Among multiples factors, co-occurrence of eating disorders such as binge eating disorder has been implicated in insufficient clinical response. Improving our ability to predict how patients will respond to obesity treatment is necessary in order to tailor the care pathways we offer. The mechanisms involved in disturbances of eating behaviour before and after surgery remain largely unknown. This study aims to identify the predictive factors of weight loss after pharmacological or surgical treatment, as well as the cognitive and biological mechanisms that mediate this effect.

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Key information

Conditions

Obesity & Overweight Body Weight Nutrition Disorders Nutritional and Metabolic Diseases Obesity Overnutrition Overweight Pathological Conditions, Signs and Symptoms Signs and Symptoms

Age range

18 year–65 year

Sex eligibility

All sexes

Study type

Observational

Primary location

Cliniques Universitaires Saint-Luc

Brussels, Brussels Capital, 1200, Belgium

Location status: Recruiting

Location contact

Audrey Loumaye, Professor

SUB_INVESTIGATOR

Dr Yannick Deswysen, Doctor

CONTACT

[email protected]

+32 (0) 2 764 22 13

Yannick Deswysen, Doctor

PRINCIPAL_INVESTIGATOR

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Age between 18 and 65 years
  • Obesity, with bariatric surgery indicated after a multidisciplinary evaluation in case of surgical treatment.
  • Good physical and mental health, enabling informed consent.
  • French speaker

Exclusion criteria

  • Legal protection
  • Pregnancy or breastfeeding
  • History of bariatric surgery (except gastric banding, provided it was removed more than five years ago).
  • Acute or progressive chronic disease
  • Alcohol consumption of more than 20 g/day
  • Inflammatory bowel disease;
  • Digestive autonomic diabetic neuropathy.
  • Consumption of dietary supplements (stanols, probiotics, prebiotics or omega-3).
  • Following a vegan or gluten-free diet or being lactose intolerant.
  • Fibre consumption >30 g/day
  • Recent change in antidiabetic medication within the past 3 months.

Treatment and study plan

Pharmacological or surgical treament of obesity

Procedure

Longitudinal follow-up of participants who initiate an anti-obesity medication or whose application for bariatric surgery was accepted. It will combine anthropometric, clinical, neuropsychological and biological measurements taken at various timepoints. Participants will be asked to complete a set of online questionnaires and data will be recorded anonymously. Biological samples will be collected at various time points.

Primary outcomes

  1. Correlation between weight loss after treatment and clinical, neuropsychological and biological parameters.

    Time frame: Throughout the entire study, aproximately during 5 years

    The percentage of excessive weight loss after treatment will be correlated with

    • Clinical parameters (Binge Eating Scale and modified Yale Food Addiction Scale 2.0)
    • Neuropsychological parameter (Barratt Impulsivness Scale and Trail Making Test)
    • Biological parameters

Secondary outcomes

  1. Binge Eating Disorder.

    Time frame: Throughout the entire study, aproximately during 5 years

    Evaluation of eating disorders using the Binge Eating Scale (BES).

  2. Food Addiction.

    Time frame: Throughout the entire study, aproximately during 5 years

    Evaluation of food addiction will be performed using modified Yale Food Addiction Scale 2.0.

  3. Eating attitudes

    Time frame: Throughout the entire study, aproximately during 5 years

    Eating patterns and habits will be screened using the Eating Attitude Test 26

  4. Cognitive flexibility.

    Time frame: Throughout the entire study, aproximately during 5 years

    Neuropsychological evaluation of cognitive flexibility will be performed with the Trail Making Test

  5. Impulsivity.

    Time frame: Throughout the entire study, aproximately during 5 years

    Impulsivity will be assessed using the Barrat Impulsiveness Scale (BIS)

  6. Self-reported quality of life.

    Time frame: Throughout the entire study, aproximately during 5 years

    Self-reported quality of life will be assessed using the QOLOD (Quality of Life, Obesity and Dietetics)

  7. Obesity.

    Time frame: Throughout the entire study, aproximately during 5 years

    Weight will be measured at each timepoint

  8. Physical activity.

    Time frame: Throughout the entire study, aproximately during 5 years

    Weekly physical activity will be reported with the Godin Leisure Time Exercise Questionnaire (GLTEQ)

  9. Food intake.

    Time frame: Throughout the entire study, aproximately during 5 years

    Eating habits will be recorded with a Food Frequency Questionnaire (FFQ)

  10. Blood samples

    Time frame: Throughout the entire study, aproximately during 5 years

    Blood samples will be collected and processed for metabolomic analyses.

  11. Fecal sample

    Time frame: Throughout the entire study, aproximately during 5 years

    Feces samples will be collected and processed to evaluation gut-microbiota composition

Other outcomes

  1. Sociodemographic data

    Time frame: Once at inclusion

    Number of children and marital status will be recorded

  2. Medical history

    Time frame: Once at inclusion

    Information concerning medical comorbidities will be collected from the patient medical record.

  3. Childhood Trauma.

    Time frame: Once at inclusion

    Assessment of adverse life events and trauma will used the Childhood Trauma Questionnaire - short form.

Study contacts

Contact information is provided by the study sponsor or research team.

Pr Amandine Everard, Professor

CONTACT

[email protected]

+ 32 (0)2 436 22 10 ext. +32

Yannick Deswysen, Doctor

CONTACT

[email protected]

+ 32 2 764 22 13 ext. +32

Sponsors and collaborators

Lead sponsor

Université Catholique de Louvain

Other

Registry information

Official study title

Research of Predictive Factors of Weight Loss After Pharmacological or Surgical Treatment in Patients Suffering From Obesity

Important dates

Study start
2026
Primary completion
2032
Study completion
2036
First posted
Feb 11, 2026
Registry last updated
May 14, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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