The claimEvidence A · guideline-tier
BMI is completely useless
The evidence
Global BMI Mortality Collaboration Lancet 2016 (n=10.6M): BMI shows a robust J-shaped curve with all-cause mortality. Imprecise at the individual level, strongly informative at the population level.
The mechanism, in brief
Body weight is a metabolic question, not an aesthetic one. Fat distribution shifts insulin sensitivity, cardiovascular event rates, joint load, sleep-disordered breathing, and hormonal axes — none of which depend on what the mirror shows, but on the ratio of visceral fat to muscle.
Sources (1)
- The Global BMI Mortality Collaboration. (2016). Body-mass index and all-cause mortality: Individual-participant-data meta-analysis of 239 prospective studies in four continents. The Lancet, 388(10046), 776–786.