Metabolically healthy obese subjects and metabolic signs of obesity in subjects with normal body weight: what is behind?

The current concept of obesity as a heterogeneous condition is discussed. Such interpretation provides a basis for distinguishing a group of obese subjects without metabolic disturbances (metabolically healthy obese (MHO) subjects) and another one including subjects with normal body weight and signs of hormonal and metabolic disorders (metabolically obese normal weight (MONW) subjects). A separate subgroup is represented by obese patients with deficit of muscular mass and force (sarcopenic obesity). Potential mechanisms underlying development of these conditions are considered along with selected applied aspects of this problem.