For decades, Body Mass Index (BMI) has been a go-to metric for assessing health, but a growing body of evidence shows it can be a dangerously misleading indicator. Health experts are urging a shift in focus from weight to metabolic health, as many individuals with a “normal” BMI are unknowingly at high risk for heart disease due to hidden cholesterol and fat-processing issues.
This phenomenon is sometimes called “TOFI” (Thin Outside, Fat Inside). A person can have a normal weight but carry a disproportionate amount of visceral fat—the harmful fat that wraps around internal organs like the liver and pancreas. This internal fat is metabolically active and can disrupt normal body processes, leading to insulin resistance and an unhealthy cholesterol profile.
Specifically, this metabolic dysfunction often manifests as atherogenic dyslipidaemia. This is a hazardous combination of high blood triglycerides, low levels of protective HDL cholesterol, and a prevalence of small, dense, and highly damaging LDL particles. This lipid profile significantly accelerates the clogging of arteries, even if the standard LDL number is not exceptionally high.
This hidden risk is why cardiologists emphasize that even for people with a BMI under 25, a modest weight loss of 5-10% can produce significant cardiovascular benefits. This small change can help reduce harmful visceral fat and dramatically improve metabolic markers, lowering the risk of a future heart attack or stroke.
The key message is to look beyond the scale. Regardless of your weight or BMI, it’s essential to get regular blood screenings to understand your true metabolic health. A “healthy” appearance is no guarantee of healthy arteries.