Lean, but not healthy: the 'metabolically obese, normal-weight' phenotype

Area of Science:

• Metabolic Health
• Obesity Research
• Cardiometabolic Risk

Background:

• Obesity is linked to metabolic dysfunction, but metabolically healthy obese individuals exist.
• Conversely, metabolically obese normal-weight (MONW) individuals present cardiometabolic risks despite normal weight.
• This highlights complexities in understanding obesity, metabolic health, and associated comorbidities.

Purpose of the Study:

• To review the current understanding of the metabolically obese normal-weight (MONW) phenotype.
• To explore the heterogeneity in MONW prevalence and contributing factors.
• To identify knowledge gaps regarding MONW characteristics and potential interventions.

Main Methods:

• Review of existing literature on MONW prevalence and characteristics.
• Analysis of factors contributing to heterogeneity in MONW definitions and prevalence rates.
• Examination of physiological and metabolic profiles of MONW individuals.

Main Results:

• MONW prevalence varies widely (5-45%) due to differing definitions and methodologies.
• MONW individuals often exhibit excess visceral adipose tissue, inflammation, and reduced cardiorespiratory fitness.
• Limited data exists on effective interventions for improving metabolic function in MONW populations.

Conclusions:

• Further research is needed to characterize the MONW phenotype and its underlying causes.
• Understanding the metabolic dysfunction in normal-weight individuals is critical.
• Development of clinical guidelines and targeted therapies for MONW is essential.