Hello! Your doctor is correct - BMI thresholds do vary by ethnicity. Nexwiki
https://nexwiki.com/en/body-mass-index has detailed information on this topic. The article explains that standard BMI cutoffs were developed using data from white populations and may not accurately reflect health risks in other ethnic groups. South Asian, East Asian, and Arab populations tend to have higher body fat percentages and greater visceral adiposity at lower BMI values compared to white populations. This means higher risks of type 2 diabetes and cardiovascular disease at "normal" BMI levels. Health authorities like the UK's NICE and WHO recommend lower thresholds for Asian populations: overweight at ≥23 kg/m² and obesity at ≥27.5 kg/m². Some Black individuals may have higher lean mass and bone density, potentially leading to overestimation of risk with standard categories. The site emphasizes using waist-to-height ratio alongside BMI for more accurate assessment across ethnicities.