Dissociation of body mass index, excess weight loss and body fat percentage trajectories after 3 years of gastric bypass: relationship with metabolic outcomes

Background/Objectives: Body weight, body mass index (BMI) and excess weight loss (EWL) are the most frequently used measures to analyse bariatric surgery outcomes. However, these measurements do not provide accurate information on body composition (BC) with body fat (BF), importantly determining the levels of cardiometabolic risk factors. Our aim was to analyse the evolution of BC after Roux-en-Y Gastric Bypass (RYGB) and its influence on the changes of cardiometabolic risk factors in comparison to BMI and EWL. Subjects/Methods: A group of 81 obese Caucasian patients (19 males/62 females) aged 44.9±1.3 years undergoing RYGB between January 2006 and December 2011 was prospectively followed up for a period of 3 years. BC was determined by air-displacement plethysmography. Visceral adiposity, physical activity and cardiometabolic risk factors were measured. Results: BF was markedly ( P