The interest in the new phenotype termed sarcopenic obesity (SO), which refers to a decrease in muscle mass and strength combined with an increase in body fat deposition – is in growing trend. However little is still known about this phenomenon in young adults affected by obesity especially in the weight management clinical setting, and therefore still needs further clarifications. In the current presentation, we firstly highlight the dilemma surrounding the definition for SO with our attempt to identify the suitable ones to use in screening SO especially in young adults with obesity. Foremost those who consider body mass (i.e., body weight, body mass index), and that have revealed their clinical usefulness. Secondly, we examine the potential association between SO and energy expenditure (i.e. resting and activity physical energy expenditure. Finally, we discuss the relationship between SO and weight management outcomes. Namely, the impact of SO on attrition rate (i.e. dropout), weight loss and weight-loss maintenance during weight management programs.