BMI and Health: A nuanced perspective

Those in the online health and nutrition space fiercely debate the connection between BMI and health status. Some argue that BMI is flawed, failing to predict poor health outcomes and fueling weight bias in healthcare.

The debate over BMI has prompted many to describe “metabolically healthy obesity” to refer to individuals with obesity (BMI ≥30) who are at low risk for obesity-associated diseases.

A recent cross-sectional study suggests that the risk of developing one or more metabolic syndrome components (high waist circumference, triglycerides, blood pressure, blood glucose, or low HDL-C) increases linearly with BMI. Of the participants with obesity, ~92.5% had at least one metabolic syndrome component, whereas 45% of those with a BMI <30 had at least one metabolic syndrome component.

Notably, a person has metabolic syndrome if they have at least THREE metabolic syndrome components rather than just one. So, perhaps the current study’s stringent criteria made it difficult to assess the prevalence of metabolically healthy obesity. The true prevalence of metabolically healthy obesity largely depends on the criteria you’re using. A 2017 meta-analysis of 40 studies reported that 35% of those with obesity were metabolically healthy. However, they were still at a higher risk for developing metabolic abnormalities than those without obesity.

While BMI is far from a perfect metric, it does correlate with metabolic health indicators. BMI can be a decent screening tool to check for other metabolic risk factors, especially among those who don’t have a lot of muscle (BMI doesn’t account for muscle mass).

Hopefully, more practitioners and influencers alike will appreciate the nuanced relationship between BMI and health. BMI is a tool — not a perfect predictor of health.

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