Why two people with same BMI can have different risks of diabetes, heart disease and fatty liver
Source Entity
The Indian Express
Body Mass Index (BMI) is an insufficient metric for metabolic health because it fails to account for body composition. Muscle mass, fat distribution, and storage locations play a more critical role in determining risks for diabetes and heart disease.
The Limitations of BMI in Modern Clinical Diagnostics
For decades, the Body Mass Index (BMI) has served as the primary clinical shorthand for assessing weight-related health risks. Calculated simply as a ratio of weight to height, it was designed as a population-level screening tool. However, as medical science advances, it is becoming increasingly clear that BMI is a blunt instrument that often fails to capture the nuances of an individual's metabolic health. Two individuals may possess identical BMI scores, yet their underlying physiological risks for chronic conditions like diabetes, cardiovascular disease, and fatty liver can be vastly different.
The Critical Role of Body Composition
The primary reason for this discrepancy lies in body composition—specifically the ratio of adipose tissue (fat) to lean muscle mass. Muscle is metabolically active tissue that aids in glucose regulation and insulin sensitivity. Conversely, excess adipose tissue, especially when stored in specific areas, can trigger chronic inflammation and metabolic dysfunction. A person with high muscle mass may be categorized as 'overweight' by BMI standards while maintaining a healthy metabolic profile, whereas someone with low muscle mass and high body fat—often termed 'skinny fat'—might fall within the 'normal' BMI range while harboring significant health risks.
Fat Distribution and Metabolic Risk
Beyond the total amount of fat, the anatomical location of fat storage is a primary determinant of disease risk. Visceral fat, which accumulates around internal organs, is significantly more dangerous than subcutaneous fat, which is stored just under the skin. Visceral fat is metabolically active and releases fatty acids and pro-inflammatory cytokines directly into the portal circulation, which directly impacts the liver. This process is a key precursor to non-alcoholic fatty liver disease and insulin resistance, which eventually leads to type 2 diabetes and cardiovascular complications.
Expert Perspectives on Metabolic Health
As noted by Dr. Saurabh Juneja, Director and HOD of CTVS at ISIC Multispeciality Hospital, relying solely on BMI provides a truncated view of a patient’s health. Clinical experts are increasingly advocating for more sophisticated assessments that go beyond simple weight-to-height ratios. By evaluating body composition, doctors can better identify individuals who are at risk for metabolic syndrome even if their external appearance or standard BMI suggests they are healthy.
Future Trends in Personalized Medicine
Moving forward, the medical community is likely to shift toward more comprehensive diagnostics, such as DEXA scans, bioelectrical impedance analysis, and waist-to-hip ratios, to provide a clearer picture of internal health. As we transition toward a more personalized approach to healthcare, the reliance on outdated metrics like BMI will likely be replaced by integrated assessments that account for muscle quality, fat distribution, and genetic predispositions. Understanding these factors is essential for the early detection and prevention of lifestyle-related diseases.