Skip to main content
OpenTrials
Completed

NCT Number: NCT07456124

Weight Loss and Adipose Tissue Metabolism During Conservative Treatment of Obesity

This prospective observational study investigates weight loss and metabolic changes in adults with obesity undergoing standard clinical diet-induced lifestyle treatment and counseling. Participants follow a very-low-calorie diet followed by a conventional weight loss diet in addition to lifestyle counseling and are followed for 12 months. The study examines weight loss as the primary outcome and characterizes changes in body composition, fat distribution, glucose metabolism, inflammation, and adipose tissue biology as secondary outcomes.

Completed

Looking for future studies?

Notify Me

Key information

Conditions

Obesity & Overweight Body Weight Body Weight Changes Inflammation Nutrition Disorders Nutritional and Metabolic Diseases Obesity Obesity (Disorder) Overnutrition Overweight Pathologic Processes Pathological Conditions, Signs and Symptoms Signs and Symptoms Weight Loss

Age range

18 year and older

Sex eligibility

All sexes

Study type

Observational

About this study

Obesity is associated with metabolic complications including insulin resistance, fatty liver disease, dyslipidaemia, and systemic inflammation. Weight loss can improve these complications, yet individuals vary widely in weight loss, fat distribution and metabolic response. Subcutaneous adipose tissue dysfunction, including impaired mitochondrial biogenesis and increased inflammation, is thought to play a central role.

This prospective observational study follows adults with obesity undergoing standard-of-care diet and lifestyle treatment at Helsinki University Central Hospital, Helsinki, Finland. The intervention consists of a very-low-calorie diet for approximately 10 weeks, followed by gradual transition to a conventional weight loss diet and multidisciplinary clinical follow-up.

Assessments are performed at baseline, 6 months, and 12 months and include anthropometry, body composition (BIA, DXA), fasting blood samples, and oral glucose tolerance testing. Subcutaneous adipose tissue biopsies are obtained from four anatomical depots (gluteal, abdominal, breast, and upper arm) for molecular, mitochondrial, epigenetic, and histological analyses.

The primary outcome is diet-induced weight loss over 12 months. Secondary outcomes include changes in fat distribution, insulin sensitivity, lipid profile, inflammation, mitochondrial measures in adipose tissue, and depot-specific adipose tissue characteristics.

Who can participate

Healthy volunteers accepted: No

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

Inclusion criteria

  • Age ≥18 years
  • BMI ≥28 kg/m²
  • Seeking treatment for obesity at Helsinki University Central Hospital or affiliated units

Exclusion criteria

  • Pregnancy or lactation
  • Current smoking
  • Anemia (Hb <130 g/L in men; <120 g/L in women)
  • Severe comorbid disease or condition judged by investigator to compromise safety
  • Contraindications to MRI (e.g., metal implants, claustrophobia)

Treatment and study plan

Diet-Induced Weight Loss Program

Behavioral

Standard clinical obesity treatment consisting of a very-low-calorie diet for approximately 10 weeks followed by transition to a conventional weight loss diet with multidisciplinary clinical follow-up.

Primary outcomes

  1. Percent Total Body Weight Loss (%TWL)

    Time frame: Baseline to 6 months

    Percentage change in body weight from baseline, calculated as 100 × (baseline weight - follow-up weight) / baseline weight

Secondary outcomes

  1. Change in Body Weight (kg)

    Time frame: Baseline to 6 and to 12 months

    Absolute change in body weight measured in kilograms (kg). Reported as mean change from baseline.

  2. Change in Total Body Fat Mass (kg)

    Time frame: Baseline to 6 months and to 12 months

    Change in total body fat mass measured by body impedance analysis (BIA). Reported as mean change from baseline (kg).

  3. Change in Body Fat percentage (%)

    Time frame: Baseline to 6 and to 12 months

    Change in fat percentage measured by body impedance analysis (BIA). Reported as mean change from baseline (%).

  4. Change in Plasma Glycated Hemoglobin (HbA1c)

    Time frame: Baseline to 6 months and to 12 months

    HbA1c plasma glycated hemoglogin measured in SI units mmol/mol, Reported as mean change from baseline.

  5. Change in HOMA-IR (Homeostatic Model Assessment of Insulin Resistance)

    Time frame: Baseline to 6 and to 12 months

    HOMA-IR calculated as fasting glucose (mmol/L) × fasting insulin (mU/L) / 22.5. Reported as mean change from baseline.

  6. Change in Plasma Total Cholesterol (mmol/L)

    Time frame: Baseline to 6 months and to 12 months

    Change in Plasma Total Cholesterol (mmol/L), Reported as mean change from baseline.

  7. Change in Plasma LDL Cholesterol (mmol/L)

    Time frame: Baseline to 6 months and to 12 months

    Change in Plasma LDL Cholesterol (mmol/L). Reported as mean change from baseline.

  8. Change in Plasma HDL Cholesterol (mmol/L)

    Time frame: Baseline to 6 months and to 12 months

    Change in HDL Cholesterol (mmol/L). Reported as mean change from baseline.

  9. Change in Plasma Triglycerides (mmol/L)

    Time frame: Baseline to 6 months and to 12 months

    Change in Plasma Triglycerides (mmol/L). Reported as mean change from baseline.

  10. Change in Plasma C-Reactive Protein Concentration (mg/L)

    Time frame: Baseline, to 6 months and to 12 months

    Change in Plasma high-sensitivity C-Reactive Protein Concentration (hs-CRP, mg/L). Reported as mean change from baseline.

  11. Change in Mitochondrial DNA amount in Subcutaneous Abdominal Adipose Tissue

    Time frame: Baseline to 6 months and to 12 months

    Change in Mitochondrial DNA Amount in Subcutaneous Abdominal Adipose Tissue, measured by qPCR as the ratio of mitochondrial to nuclear genes. Reported as a mean change from baseline.

  12. Change in Mitochondrial DNA amount in Subcutaneous Breast Adipose Tissue

    Time frame: Baseline to 6 months and to 12 months

    Change in Mitochondrial DNA Amount in Subcutaneous Breast Adipose Tissue, measured by qPCR as the ratio of mitochondrial to nuclear genes. Reported as a mean change from baseline.

  13. Change in Mitochondrial DNA amount in Subcutaneous Upper Arm Adipose Tissue

    Time frame: Baseline to 6 months and to 12 months

    Change in Mitochondrial DNA Amount in Subcutaneous Upper Arm Adipose Tissue, measured by qPCR as the ratio of mitochondrial to nuclear genes. Reported as a mean change from baseline.

  14. Change in Mitochondrial DNA amount in Subcutaneous Lateral Upper Thigh Adipose Tissue

    Time frame: Baseline to 6 months and to 12 months

    Change in Mitochondrial DNA Amount in Subcutaneous Lateral Upper Thigh Adipose Tissue, measured by qPCR as the ratio of mitochondrial to nuclear genes. Reported as a mean change from baseline.

Sponsors and collaborators

Lead sponsor

University of Helsinki

Other

Registry information

Official study title

Adipose Tissue Metabolism in Obesity and Diet-Induced Weight Loss: A Prospective Observational Study of Body Weight, Fat Distribution, and Tissue-Specific Metabolic Adaptations

Acronym: 4FAT

Important dates

Study start
2014
Primary completion
2016
Study completion
2016
First posted
Mar 6, 2026
Registry last updated
Mar 6, 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.

Related clinical trials

Published trials that share one or more normalized conditions with this study.