It's an incredibly strong correlation. Very few people with BMI over 30 have under 30% body fat: https://www.researchgate.net/figure/BMI-versus-total-body-fat-p

It's an incredibly strong correlation. Very few people with BMI over 30 have under 30% body fat: https://www.researchgate.net/figure/BMI-versus-total-body-fat-percentage-based-on-muscle-mass-status-and-age-Graphs-show_fig1_324466220 https://www.researchgate.net/figure/BMI-versus-total-body-fa... There are some exceptions like professional bodybuilders (often with the aid of steroids), but we're talking about reasons why mortality rates are linked to BMI, not declaring absolutes.