van der Kolk BW, Muniandy M, Kaminska D, et al. - Researchers desired to know how subcutaneous adipose tissue (SAT) mitochondria change following diet-induced and bariatric surgery-induced weight-loss interventions in four independent weight-loss studies. The DiOGenes study is a European multicenter dietary intervention with an 8-week low caloric diet (LCD; 800 kcal/d; n = 261) and 6-month weight maintenance (n = 121) period and the Kuopio Obesity Surgery study is a Roux-en-Y gastric bypass surgery study (n = 172) with a 1-year follow-up. Weight loss induced by diet contributed to a significant transcriptional downregulation of oxidative phosphorylation, whereas upregulation accompanied weight loss induced by surgery. Differentially regulated SAT mitochondria-related gene expressions indicate qualitative alterations between weight-loss interventions, offering insights into the potential molecular mechanistic objectives for effective weight loss.