The study finds that obese people -- those with a BMI of 30 to 34.9 -- have a 44 percent higher risk of death from any cause compared with those in the most-favorable range. Severely obese people (BMI over 35) have an 88 percent higher death risk. And the most obese (BMI over 40) have a 250 percent higher risk.

Is a BMI of 14 dangerous?

BMI distinguishes anorexia from other eating disorders and provides a baseline for monitoring trends. A BMI below 14, or precipitous weight loss (>1kg/week), is dangerous. Mortality is increased by purging or substance abuse.

Is a BMI of 13 deadly?

In males, a BMI of around 13 appears to be fatal. The coefficient of variation (CV) of the BMI is 8.7%. In contrast, females survive to a lower BMI of around 11, although with greater index variability (CV 14%). Several females had BMI's as low as 9 and 10.