Understanding Sarcopenic Obesity in Terms of Definition and Health Consequences: A Clinical Review

Background and Aim: Research interests in a new phenotype termed as sarcopenic obesity (SO), which refers to a decrease in lean body mass and muscle strength associated with an increase in body fat deposition, have grown. However, neither SO definition nor its impact on health outcomes is clear. In the current paper, we aim to summarize the available literature on the dilemma surrounding the definition of SO, and the potential health consequences of this phenomenon on individuals with overweight and obesity. Methods: A literature review using the PubMed/Medline database was conducted and data were summarized by applying a narrative approach, based on clinical expertise in the interpretation of the available evidence base in the literature. Results: Some definitions that account for body mass (i.e., body weight, body mass index) seem to be more suitable for screening of SO and revealed as clinically useful. The association between SO and certain health outcomes has also been investigated, especially those related to obesity; however, little is known about the association of SO with psychosocial distress and health-related quality of life impairment, as well as harsh outcomes such as mortality. Conclusion: International consensus regarding SO definition is needed, which would allow for a better understanding of its prevalence. Moreover, future investigations should be conducted in order to determine whether SO has an adverse effect (i.e., cause-effect relationship, in addition to association) on health. Once these issues are achieved, confirmed and clarified, evidenced-based protocols of treatment may become necessary to address the increase in the prevalence of obesity and sarcopenia worldwide.