Does Metabolically Healthy Obesity Really Exist: Going Toward New Definitions.

Area of Science:

• Endocrinology
• Metabolic disease research
• Obesity medicine

Background:

• Obesity is a complex chronic disease with varied metabolic profiles.
• The concept of metabolically healthy obesity (MHO) is controversial due to inconsistent definitions and clinical relevance.
• Individuals with similar body mass index (BMI) can display different cardiometabolic risk factor levels.

Purpose of the Study:

• To review obesity phenotypes using the Lancet Commission's preclinical/clinical obesity framework.
• To evaluate the validity and clinical utility of the metabolically healthy obesity concept.
• To propose an alternative framework for classifying obesity based on organ function.

Main Methods:

• Conducted a narrative review of PubMed-indexed studies.
• Focused on the preclinical/clinical obesity framework from the Lancet Commission.
• Prioritized large epidemiological cohorts and mechanistic studies with detailed phenotyping.

Main Results:

• The metabolically healthy obesity concept suffers from inconsistent definitions and poor long-term stability.
• Emerging evidence supports a disease-based framework differentiating preclinical obesity (excess adiposity, preserved organ function) from clinical obesity (organ dysfunction).

Conclusions:

• The preclinical and clinical obesity framework offers a biologically grounded, actionable model.
• This function-oriented approach aligns obesity classification with organ dysfunction and disease progression.
• Adopting this continuum-based model can improve risk stratification and therapeutic guidance.