If you are too skinny or too heavy you have a higher risk of fatal injury in certain car crashes(reg):
Male drivers with a body-mass index (BMI) greater than 35 or lower than 22 were significantly more likely to die after front-end or left-side collisions, compared with men with intermediate BMIs, reported Shankuan Zhu, M.D., Ph.D., and colleagues at the Medical College of Wisconsin here.
Moderately overweight men (with BMIs around 28) were least likely to die, compared with their larger or skinnier counterparts,
One reason is that vehicles are not designed for you:
Current vehicle cabin designs are based on a standard crash test dummy in the driver’s position with a BMI of 24.3, the authors said.
“These cabin designs may not be optimal for drivers with a different body habitus and may contribute to the higher fatality seen at both ends of the BMI continuum,” the authors concluded.
This seems another good incentive to maintain yourself in reasonably good shape!
I wonder, though, if we will start seeing law suits by families of dead heavyweights claiming unsafe design or misrepresentations about safety.