Core tip: Obesity is a global public health problem due to its association with several diseases and reduced lifespan, as result of complex interaction of genetic, nutritional, and metabolic factors. The term of adiposopathy clearly defines the pathogenic role of adipose tissue. Four phenotypes of obesity have been described, based on body fat composition and distribution: (1) normal weight obese; (2) metabolically obese normal weight; (3) metabolically healthy obese; and (4) metabolically unhealthy obese. Sarcopenic obesity has been characterized, related to all the described phenotypes. Body fat percentage and genetic polymorphism have to be evaluated to personalize the best bariatric surgery intervention