Advances in Phenotyping Obesity and in Its Dietary and Pharmacological Treatment: A Narrative Review

Abstract

In recent times, it has become evident that there are individuals who, from a metabolic point of view, are affected by obesity but have a normal body mass index. There are also metabolically healthy individuals with a high body mass index who are thus are considered as to be affected by obesity obese. Understanding that individuals with obesity are phenotypically heterogeneous is a relatively novel concept which, although present in the scientific literature, unfortunately has not yet had an impact in clinical practice. However, common dietary approaches are not effective in treating large numbers of obese patients with obesity. This narrative review, based on the material searched via PubMed and the Web of Science up to October 2021, proposes a downsizing of the role of the body mass index in identifying the individual with "true obesity" since it is only partially useful, and suggests a new approach which also integrates the body composition and assessment of metabolic parameters. This approach leads to personalized therapies that work best for each obesity phenotype in reducing the risk of non-communicable diseases.

Keywords: body composition; dietary treatment; fat mass; muscle mass; obesity; obesity phenotypes; sarcopenia.

Figure 1

Anthropometrics and other clinical characteristics of obesity phenotypes and sub-types. MUN, normal-weight obesity; MHO, metabolically healthy obesity; MUO, metabolically unhealthy obesity; LP, lipodystrophic phenotype; NOW, normal-weight obesity; MONW, metabolic obesity normal-weight; SO, sarcopenic obesity; no-SO, no sarcopenic obesity; GL, generalized lipodystrophy; PL, partial lipodystrophy; BMI, body mass index; FM, fat mass; ASMM, appendicular skeletal muscle mass; MS, metabolic syndrome; T2DM, type 2 diabetes; NCDs, non-communicable diseases.

Figure 2

Key strategies for management of the different obesity phenotypes and sub-types. *Patients taking SGLT2 inhibitors should avoid KD; MUN, normal-weight obesity; MHO, metabolically healthy obesity; MUO, metabolically unhealthy obesity; LP, lipodystrophic phenotype; NOW, normal-weight obesity; MONW, metabolic obesity normal-weight; SO, sarcopenic obesity; no-SO, no sarcopenic obesity; GL, generalized lipodystrophy; PL, partial lipodystrophy; MD, Mediterranean diet; DASH, Dietary Approaches to Stop Hypertension; KD, ketogenic diet; GLP-1 R, glucagon-like peptide-1 receptor; ASO, antisense therapeutic oligonucleotide.