text: what does bmi mean on the biggesst loser ?   the body mass index is a useful measure of an individual's current weight related to an ideal body weight. an ideal bmi is generally between 20.5 and 21.5. a bmi greater than 30 (usually what you find on the biggest loser) is associated with increased cardiovascular risk and other health problems related to obesity.   here's a calculator to figure out your bmi: http://www.preventdisease.com/healthtools/articles/bmi.html