Long-Term Prospective and Controlled Studies Demonstrate Adipose Tissue Hypercellularity and Relative Leptin Deficiency in the Postobese State

Context: Enlarged fat cells and leptin hypersecretion are hallmarks of common obesity. Objective: The objective of this study was to investigate fat cell size and leptin production in the basal state after long-term steady-state weight reduction to the nonobese state. Design: This prospective case-control study had a duration of 3 ± 1 (mean ± sd) yr. Patients: Twenty-five obese women (cases) were studied. Each case was compared with a control subject matched for age, sex, and body mass index (BMI) at nadir of weight for the cases. Setting: This study was conducted at Karolinska University Hospital (Stockholm, Sweden). Intervention: The subjects were followed until they reached a steady-state weight reduction after lifestyle modification or bariatric surgery (cases). Treatment target was the nonobese state (BMI < 30 kg/m2). Subcutaneous adipose tissue secretion of leptin, serum leptin levels, and fat cell volume were determined after an overnight fast. Results: Ten obese women (40%) reached the nonobese st...